However, I would like to remove the hundreds of friends and pages that I don't talk to/don't represent me/are mining my data even more than the platform is.
Specific procedure I’d recommend is to make this a regular process: open fb feed, read until you find a thing which does not improves your life, click on owner (author / group) -click “friend” -> unfollow. Iterate until sanity is restored.
And one moral of this story (hi Facebook, please understand this) is that people are multidimensional. Just because you know someone once, in one context in real life, does not, actually, imply positive relationship on informational ecologies for all time in the future. “Authentic self” as defined by Facebook as a single coherent identity is a lie.
People change. I had friends who would post tireless political rants that just post memes now.
But slowly started getting requests from many of the previous friends. Some thought I had unfriended them, so had to explain to them that it was a new account. Felt obligated to add back most of the people. Now my feed is useless again.
Perhaps this should be yearly ritual.
This way, you can add people you want to, and you'll not get requests from people you're hiding from.
There was just nothing, or so little, that 'improves my life' as you put it, nor anything close. Just shit and drivel.
And it's not made for it. Quality doesn't equal traffic, nor even engagement in a monetisable sense. If it were, it would very quickly have learned that I didn't want to see memes, full stop. Nope, feed continued to be full of valueless memes.
For a brief period I considered I might be 'missing out', but it doesn't take long to realise that if you're missing out through not being on the right social media platform... who or what exactly are you missing out on.
Then I added back the few that were actually important. Huge quality of life improvement.
You can explicitly mute people as well or even just certain websites. My aunt has been posting a ton of weird alt-right news lately and I've had pretty good success by just blocking her news sources so I can still see posts from her that I care about (family stuff.)
I also have a few friends who I've muted entirely because I still want to be able to contact them, but I really don't care about any of the stuff they're posting to facebook.
This might be a little more manual than you want, but it's pretty simple to just casually block posts you don't like as you scroll through your feed.
I also don't really scroll the feed anymore, so I'd rather just keep it to people I want to keep tabs on (close family, professional contacts)
Not sure if that's still the interface today, but it worked for me back then.
* Edit: I checked, and you can still do this. It's under the main preferences dropdown -> News Feed Preferences -> Unfollow people and groups to hide their posts
It's no longer a checbox, but you can simulate a click in JS. Haven't tested so obviously YMMV