Facebook has like many thousands or even hundreds of thousands really dead accounts ( of dead people ), some of those accounts are just Oculus accounts as they got forced to create a facebook account, but i think those are very low in the hundreds or with low probability in the thousands.

LinkedIn isnt really a social network for me, its rather you state your past work and current work only then to get invited to 6 sessions of coding reviews.

Twitch is a entertainment platform ( like youtube ), not social media.