Like Friendster, ClubHouse, and MySpace, there is a life cycle for every app. All the redisign and rebranding can't cure a good idea that has festered into a bad idea.
Facebook's tenure has been long indeed, but it's best time has likely passed.
Many people also don't realize the tactics that platforms use to try to uphold the illusion that they are still active, including paying influencers to post, and in even creating totally fake accounts. I won't say any names, but this is why most sites no longer publish their active user numbers like they did when they were growing, because many were caught as well back then in overstating their active user numbers.