I think Instagram has gotten quite a bit worse over the past few years. I really only want to see posts from people I follow and they've made that more difficult.
The service that totally baffles me is Tik Tok. I know it's supposed to learn what you like, but it has never really surfaced anything of interest to me. It might even be worse than YouTube for me.
My ideal Instagram algorithm would be to show me only the people I follow, in chronological order. Then show me a marker that I'm at the end of my feed and at that point they can offer me their feed.