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.
Some. Other than basic anti-tracking add ons, Facebook Container is one, and so is Social Media Fixer, which will block whatever you tell it to on FB. I block all “suggested for you” as a keyword and it removes so much junk from FB. I have a couple more I think that help FB be more like its old self, but unfortunately I’m not home and can’t look them up right now on mobile.