That is a good book.
Re: downvoting; I think it’s just knee jerk reaction to any suggestion Facebook can do anything good. I have the same reaction but, like you, there’s a specific group I belong to that doesn’t exist elsewhere and it’s one of the few groups that isn’t toxic or hysterical.
Does GtS not support relays? That’s what everyone uses to seed their new instances. I’m on a single user instance and have thousand of posts from hundreds of instances coming in daily.