I uninstalled the Facebook app, and use the website. It's 90% as good in functionality, and 1000% better in what it can and cannot do with data on my phone.
(If you post and comment regularly, you may prefer the app. I mostly use the site for casual browsing, and checking the address of events I'm on my way to.)
They're separate apps, not sure why you don't get them from messenger.
I've left that one's notification access open because at least for now it only uses them for someone sending me a message. Fingers cross they don't move the "SOMEBODY JUST WENT LIVE WITH VIDEO!!!!" over to that.
(If you post and comment regularly, you may prefer the app. I mostly use the site for casual browsing, and checking the address of events I'm on my way to.)