Possibly the wrong place, but personal server questions
I'd like to set up a personal cloud, probably through a vps to start. However, I'd also like to move my domains to the same server. It's been well over a decade since I did any server admin style work, so in technology years I'm old as feck.
What are my best options to look into as far as privacy/security/reliability/price for a vps? What are my best options to allow friends and family to mindlessly backup their data to our private cloud (if such a thing exists)? I'm looking for cross platform support and the ability to host multiple websites.
ownCloud is probably something to check out. Or their competitor, Nextcloud. I haven't used either, but they've been around a decent amount of time. I think ownCloud was a thing when I was last doing VPS stuff in 2016, so I'm also out of practice.
Linode used to be the premiere VPS provider, but recently made changes to the service or plans. I think they were acquired? A dev who I listen to on some podcasts talked about how he was gonna have to make changes to his business because of stuff after changes rolled out on Linode, so keep that in mind if you end up reading forum posts from >6mo ago recommending Linode.
I've heard both of those suggested quite often. I've been researching those a bit, especially from when they split from each other on. I was curious to speak to an actual user about their experiences, or if there are other alternatives
I personally use and recommend nextcloud. I choose it due to licensing (nextcloud is 100% open source, whereas owncloud has an open source edition with the enterprise edition being propietary).
Besides that, the main difference between owncloud/nextcloud is that owncloud feels more "enterprise" oriented and offers its professional service as a 1st party SaaS, while nextcloud offers the service mostly through partners (like Hetzner, Ionos, Fujitsu...). However in both companies the 1st party services are quite "big" and expensive for most of us mere mortals (minimum of 25/100 users, with pay per user). You probably will have enough with self-hosting or 3rd party providers.
Also although in the past it took a while for nextcloud to really differentiate itself from owncloud and gain traction, currently nextcloud development moves REALLY fast, which is a great thing for its capabilities (but a bit of extra work and headache to maintain a self hosted instance up to date), and the software has improved drastically in the past years.
From what you are describing, hosting your own nextcloud seems to fit your needs perfectly. Since you also seem to need websites, maybe a VPS instance with tons of storage where you deploy and manage your own service? If you go this way, as other have commented, I would recommend learning and using the docker images, since they will make your life easier in the long run, and will help with the websites/nextcloud living together happily in harmony.
However, for security, I personally recommend to separate the hosting and nextcloud services. I use a managed nextcloud instance (for ease of mind: someone else takes care of the updates, back-ups and security of my storage), and then the website hosting in a different service, so if I make a mistake in my web server I don't risk my personal or family files. I have experience and currently recommend Hetzner for the NC instances (Storage Share), but also have worked successfully with Scaleway using a compute instance to self-host nextcloud, linking it to their Object Storage for the filesystem.
With NC you can create subdomains, assign users and set quotas, define what they can do or not (like for example, sharing files or folders outside of the instance, for how long, allow public uploads...), lock down the instance with 2FA and IP filtering... Nextcloud is really customizable, and has a lot of possibilities if you want to extend it through the apps (like collaborative document editing, or audio/video conference). I have used it for several years with the clients in Linux, Android, Windows, and once you configure it as you want, it simply works.
If I'm a MetaARPA member with SDF I have access to their NC, so I wouldn't have to manage that aspect? How does that work? Or should I still be researching self hosting? The websites aren't business, just family and hobbies and fooling around learning new tips and tricks and playing with shiney objects so that's more or less just my personal playground for now and not a primary concern. Migrating away from walled gardens and controlling my own data is what matters to me right now
I am not sure what are the conditions/benefits provided by MetaARPA level, but my guess is that any NC access would be provided only to your specific SDF account, and with limited space/bandwidth.
And if you plan to offer family/friends with access... Well, I wouldn't want auntie Alice to see uncle's Bob backup folders and say "oh, I don't need any of this crap, I will delete it so @jdh knows how a nice user I am".
Save yourself some headaches and consider the basic plan from hetzner (https://www.hetzner.com/storage/storage-share), and just create a user (with quotas!) for each member that needs access. The service literally takes care of everything, and you only will need to remember to check that your apps are still properly enabled after they perform any updates or maintenance (and they will be perfectly fine 99% of the times, with the other 1% just requiring you to click on enable/update for some specific app).
Learn from there and then you can grow to bigger plans or, if you really feel the need to it, go full ahead hosting your own instance (maybe initially a cheap droplet in digital ocean, or a compute instance in scaleway, so you can learn the basics and break things). Next level? Pick a bigger instance or one of the real servers from hetzner's auction and go nuts. But always remember: auntie Alice won't be happy if your tinkering risks her collection of funny cat pictures. Always keep a backup of the backup (and test that it works!)
Always consider that just moving into nextcloud gives you much more control over your data than with any google/microsoft/somethingsomething service, since you can always just launch another nc instance anywhere else and move everything there. But at the end you ALWAYS must trust someone (your providers, your vendors... your users) and if you REALLY are paranoid about some unauthorized actor accessing your information, then self hosting in your own dedicated hardware is your only way, and that costs time and effort.