As for Facebook, I never deleted it since I use messenger all the time to plan things with friends and family. But I never visit Facebook the website. I just don't visit it.
Mom and pop stores publish their opening hours on facebook, semi governemental entities requiring facebook to enter their site, etc...
I think I follow 15 people right now and for me it is perfect. I will sometimes try to add new people but the moment someone posts something political or if they pass a threshold for posting too much useless content I instantly block them. I also don't follow anyone I know personally and can just txt them.
For me, my twitter feed is a phenomenal resource and an absolutely life positive thing. The problem though is the whole platform would collapse if everyone used it as I use it.