Not exactly. (I’m new too) The “Following” feed is just posts by people you follow. The “Discover” feed has some sort of algorithm, but it seems a little random to me. You can add feeds that are simple (posts by certain users) or have an algorithm (posts about astronomy).
Just to add a note here. The following feed is people you follow along with feeds you follow. It's in no particular order though and you will miss many posts from people you follow.
Comments
No idea how it determines what you see.
Go Al!
Go Al!