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 was resistant to ending my use of reddit, but now they have nerfed the mobile site so bad I can’t even login anymore so I’ve stopped trying. I still peruse it on my PC at least once daily but I think that the moment RES finally stops working will spell the end of that.
As for Facebook. I mostly keep it around for an easy connection to family and friend and a few meme groups that amuse me. But again, only like once a day do I check in ion that site.
Edit: I should mention that I have never and will never use either of those website’s apps.