Honestly I'm amazed. Old Reddit is still functionally unchanged over the past several years and honestly a great experience. And Reddit must know exactly how many people are using it because they're visiting an alternate domain.
You can use it on mobile by using Firefox Nightly, enabling the add-ons collection workaround, and installing the old.reddit redirect addon (and uBlock).
Granted, browsing old.reddit on a mobile screen is not a great experience but it's leagues better than the alternative.
At that point I'm more comfortable on Lemmy instead of bending over backwards to accommodate for shitty Reddit UI anymore. I used to use old reddit but that was when I actually had time to waste in highschool pretending to do work on the school computers, now I have a newborn and would never scroll on my PC to just browse Reddit, or any social media for that matter..