I lived in Spain for 5 years and then I returned to my country 13 years ago.
Some 8 years ago, Facebook was something that I really enjoyed using. I left way too many friends, close friends, and well, lovers behind. Facebook allowed me to have a healthy relationship with them, even if at a distance.
I went back to Spain on 2010 for the wedding of a close friend, and it was like I've been out of the country for 2 months instead of 2 years, and that was mostly thanks to Facebook.
I can't point exactly at the moment when all that went to shit (May be 5, 6 years ago?) but nowadays FB is a constant string of shitty videos from companies trying to stay afloat, shitty videos made by shitty people, fake news by the thousand - and people adhering to the fake news narrative! - and stupid motivational shit of the kind that really demotivates you, people viciously attacking other people for the stupidest reasons...
I disabled my account some 3 months ago, and I feel much better without it.
Instagram, on the other side, is a different beast. Even with the strong push by FB in order to monetize the network, I think that fact that people can't easily share other people's post, and are kind of forced to post their own material still makes it an interesting place.
As long as instagram does not allow reposting, I think it'll maintain a certain degree of quality.
I also have disabled my insta account, but I do miss the information from the people I was following there (Mostly, artists and crafstmen of all kinds).