is using old.reddit.com okay to use

You're asking two questions here. One is about some kind of purity test, which... You gotta let that one go. The crowd isn't here to pass judgement on you, and asking it to do so is a kind of psychological self harm.
The other is about whether using a particular Reddit front end supports Reddit. The answer to that is an unqualified "yes".
The two together point to you wanting to use Reddit, but not wanting to be judged poorly for doing so, and that's an anxiety state you don't deserve to live in. You either believe strongly enough about not supporting Reddit for your own reasons to not use it, or you don't. And that's ok, because they're your beliefs. You're not some soldier in some holy war.
- Are you some kind of wizard

No. Engagement metrics feed into the IPO valuation and I won’t willing give u/spez the sweat off my nethers. Don’t even go there.

It's just another frontend for normal reddit. Literally the same as using reddit.

No.
Reddit is also anonymous
Why would you use a site that lies to you?
- Why would you use a site that lies to you?
  You honestly expected them to tell you the truth?
  They are in the run up to an IPO, they are trying to pump up the numbers as much as they can. I don't like what is happening to the place but I am not naive enough to think it would not happen.
  Reddit has been going for 18 years and has been relying on VC money all that time, it could not last forever.
  Eventually someone had to pay the bills.
  I am surprised it lasted so long as it did in the form it was in.
  
  lmao. Reddit had $456,000,000 in revenue in 2021. It would've been profitable long ago, except it's CEO spent millions and millions of dollars on buying and shittifying an app for it, chasing reddit NFTs and reddit crypto, creating a 'new' user interface that every user loathes, creating a streaming platform that died within a year, deciding to pay large infrastructure and bandwidth costs by changing to self-host videos and images after a couple decades of successfully out-sourcing that to other platforms, destroying AMAs, happily platforming and aggressively resisting de-platforming child porn, white nationalists, insurrectionists and other questionable groups, aggressively alienating the people who were happily creating and running the forums, creating new 'games' to be run for one single day, and a whole bunch of other stupid or questionable shit.
  Huffman's been happily cruising away on infinite VC money for, what, eight years now? And he woke up one day six months ago to realize that he'd paid tens of millions of dollars for multiple incredibly rich companies to mass-harvest one of reddit's two prize assets, and he fucking panicked. Man has no vision beyond whatever shiny new techbro ponzi scheme is currently popular, except he gets on them too late and in ways that won't work, and he has absolutely no business trying to run a business - he just lucked into it and he knows that no one will ever hire him to run one again so now he's desperately trying to make a silk purse out of a pig's ear so that he can IPO and cash out before he gets (rightfully) fired.
  
  Reddit was sustainable back before they started chasing profit and hiring absurd amounts of staff. They used to be able to cover their server costs with gold alone. It was only once they hired literal thousands of employees that they started needing to needle their users for money
- Using the old one would be supporting spez? I need more access to learning resources and experiences; which is what I used to use "read it" for but have since been browsing the limited resources on the lemmy instances. Anyway to figure out if the answers to a certain question on one instance is in another instance?
  
  Using reddit is using reddit, regardless of how you access it.
  But you probably shouldn't worry too much - the fact remains that there's a ton of old, useful content that can be only found on reddit, so sometimes you don't really have a choice.

nobody is watching what youre doing and all this lemmy shit is theatrics just live your life how you want to live it restrictions are for people that think they have a bigger purpose. nobody has a bigger purpose.
unless of course that restriction is a healthy dietary and physical change in lifestyle. that is a good purpose but everyone should be doing that.
- That’s horrible advice. You should be ashamed of yourself.
  
  Telling someone to live their life how they want is horrible advice?
  
  Why is it horrible advice?

You use whatever you want to use. Come to your own conclusions, don't ask other people to tell you what to do.

Restricting your access to the site is a form of individual consumer activism, and I don't think that ever really makes a difference.
The thing that will kill reddit is their enshittification leading to an exodus of content creators and the subsequent exodus of casual users.
The tiny influx of traffic you give them when you look something up occasionally isn't going to make any difference. I visit it when it has answers, but it's about 1000th of my previous activity and I no longer submit anything.
You may as well lower hay bales off the boat deck of the Lusitania. Yes it will reduce its weight but it's still been hit by a torpedo. It's going down; it's inevitable; don't stress about it.
I hope all the useful posts will be archived somewhere and accessible later. That's perhaps the best outcome we can hope for.
- When I talk about an archive I mean one that isn't in their power, like the wayback machine. I'm not going to start using onion sites just for an embargo that I believe is irrelevant and ineffective.
- Both thinking and communicating that individual actions are futile is counterproductive. Close to zero is still non-zero. Be the change you want to see.
  
  I disagree. I think that thinking and communicating that individual consumptive action is effective is harmful. I highlighted "consumptive" because it is a key term that you omitted.
  The fossil fuel industry pioneered it as their "carbon footprint" propaganda in a deliberate attempt to distract our attention away from their responsibility and away from collective action against them. They want to individualise our efforts so we won't unite against them, and this idea was effective in achieving that.
  The collective action alternative to an absolute boycot of reddit is... right here. It's lemmy. I'm not there on reddit making contributions and comments and voting, I'm here, and I'm also not making links to reddit. If I had to I'd either copy the relevant info or link to an archive. Together we are collectively building the alternative. It is not the same thing as setting a complete "don't visit reddit" embargo. Visiting reddit once or twice a week because it has answers to technical problems that I can't find elsewhere is my individual consumptive action, and it isn't a blip on that.
  If you're on the deck of the Lusitania rearranging chairs, you're not spending the limited time you have in finding a way off the ship. Your actions didn't sink the ship and they won't save it. It's not almost nothing, it is less than nothing because energy spent on it is wasted energy.
  Now I'm interested in why you think individualised action is so important - but remember I am highlighting the concept of individualised action to separate it from collective action. I just wrote a lot of words on what I think is the theoretical basis of this kind of thing but I decided to spare you from it unless you asked.

Go for it.

Look, if you are looking to use reddit without supporting it, your best bet is to:
-1 Browse with ad blockers so they get no revenue from you.
-2 Never post anything. A post is free content for them. If you have to ask a question, delete the post afterwards.
-3 Never comment on anything. Again, that's free content for Reddit. If you have to comment, delete it after a few days.
-4 Never up/down vote anything, or report anything. Reddit wants you to curate their content for free, fuck that!

They still serve ads on old Reddit, so you're still giving them money and metrics. Really depends on why you left Reddit in the first place
- What if you run an adblocker and never see ads? Then to me the only way you are contributing to Reddit income rather than costing them money is by commenting and voting.
  
  Even just being on the website boosts their monthly active users number which they can use to convince advertisers to buy ad space.

Its days are numbered anyway.

Yes it is ok to use old.reddit. (it was the only way i would ever access the site)
There are still several subs that have content I cannot get anywhere else, so I still visit now and then.
I check the subs via RSS, then open and threads I want to read in old.reddit as I have not found a way to access comments via RSS.
is using it still in support of spez?
If you are using an add blocker they are not gaining any revenue from your visit.
Yes, you do still count in traffic numbers...but the world is not perfect.
In conclusion: Visit when you want.
- Policy updated yesterday where you can't opt out of data farming. They are openly stating that they are selling targeted data about every link you click on, sub you subscribe to, anything you up and down vote. Not that I don't think they weren't doing this in some fashion already, but the option isn't even there anymore. They aren't trying to hide it and are basically gaslighting people and trying to tell them it's actually a good thing you can't opt out.
  
  I understand that is upsetting but I look at it this way.
  I never use the web without ff and ublock, both on pc and mobile (android + ff + ublock) I literally never see adds.
  youtube is also via ff on both so no adds as well.
  So the personalisation of ads means nothing to me as I never see them

I do not support providing any more traffic to Reddit (which is why I blowed out my 7 years old account last week) - but there was a time during mid-July when I was still keen on giving Reddit a last chance, and I was exclusively using old reddit with "Old Lander" user script via Tampermonkey, which made it a terrific interface for mobiles.
You might give it a try
https://github.com/OctoNezd/oldlander
But in the end fuck spez, and I am a lot more peaceful now after deleting my Fuggit account.
PS : I did not write Old Lander script, I just found it to be awesome while I was using it.

The app sink it for Reddit https://apps.apple.com/at/app/sink-it-for-reddit/id6449873635 is excellent.
I use the official Reddit app to keep up with porn. I also interact, upvote, downvote, comment on these. But nothing else.