5-6 hours seems excessive... If you have other issues that are the root cause, maybe deal with those first, but if it's a self-control issue (which it was for me sometimes) there are great browser plugins to block certain sites after a certain amount of time. I use LeechBlock for firefox and after my "self allotted time" it locks down reddit and lemmy for me so I can't access it any more. There are similar plug ins for other browsers, I can really recommend it!
Ps: But to answer your original question, from an ideological standpoint, definitely stay on lemmy.
Yes. "The internet never forgets" is actually a thing.