SLA? If that means something like “service level agreement” (I don’t know, you didn’t specify, I’m guessing) then I can still find examples where it falls well below what I would expect from a public service such that if there was an agreement in place that I would definitely be opposed to it as a tax payer.

And if X isn’t viable there are other platforms that are.

I mean yes obviously, there are much more viable platforms like Mastodon, or even a self-hosted website.

Is Twitter/X viable for that? They can decide, and have, to randomly put information behind login walls.

If based on the thing I used most then it has to be Firefox!

If you want something more trivial but personal, openttd - the best game ever. :)