Are you using the app or browser? I just use Safari on iOS and I only follow my two kids and I just go back years of posts and there’s nothing from strangers on there.
How long has it been since you updated the app? It used to work that way, but they changed it. It was a really disappointing shift. If you have a pending update from ~last year, don't update until you have to. I only get a few new posts from friends each day, so it's three scrolls and bam, random accounts and content ads. To see old posts from your friends, you have to click a button that says "See archived posts" after the last new post by a friend, but before the inserted ads and strangers.
