Firefox’s Enhanced Tracking Protection (Strict Mode) is known to cause issues on x.com
There were no “issues”; everything was working completely fine. This is a deliberate decision to force people to turn off tracking protection.
I saw a recommendation to use Firefox’s container extension https://support.mozilla.org/en-US/kb/containers, but it’s disabled in private browsing windows, and I always use private browsing windows.
I personally locked my account, and only going there to “spy” on some people only being active there, or to interact with some mutual. It’s too much of a toxic pit, the porn bots now even post illegal stuff, and the site is buggy. It was quite good for my mental health to delete that app from my phone though. I miss the community I had there, some I’m instead in contact on Discord (I have a Matrix account too, haven’t been using it much), some on Mastodon. That community was slowly disappearing since the Musk takeover, not because of my absence from what is now basically just a 4chan that is still somehow attracts corporations. I wonder if I manage to find a new one soon, or maybe even create my own.