Not only was that Friends tab not there for me by default, but it also does not do the aforementioned when I customize the top(? not bottom) tab bar to I include it. What it does is to show me a list: of pending friends, and friend requests. No space to show any posts to begin with. To see my friends' posts, I have to click the hamburger, then Feeds, then Friends, then (sometimes) manually pull down to refresh, because it usually just lies to me that I've already caught up. This is designed to be actively user-hostile, as if they were forced to implement this against their will.

The Friends tab for me brings me to the actual friend feed you mentioned last but also includes pending requests and some other top matter.