Obviously, FB, twitter, insta, LinkedIn etc. are a toxic cesspool. I've left my accounts there pretty much dormant for 10+ years.
Ideally, I'd have maintained connections and contacts with my own network, using my own media, direct emails / texts, phone calls, in contexts that I controlled. The problem is... I didn't. I basically just buried my head in the sand and withdrew.
I guess the takeaway is to try to use these platforms in a positive way, as a means to an end, and not get sucked in, or to network in some other, better way, rather than withdrawing, because that's not actually a good alternative.