Ugh, I feel you! The "why does Facebook keep saying session expired" thing is so annoying. I had the same issue last week, and it turned out to be a problem with my browser extensions. I disabled a few sketchy ones, and it worked fine after that. Maybe check if you have any extensions messing with cookies?
Also, try logging in from a different browser or device to see if it’s just your phone acting up. Hope this helps!
Also, try logging in from a different browser or device to see if it’s just your phone acting up. Hope this helps!