Unfortunately Active or Top just serves me the exact same posts I scrolled through previously in the day. Not sure if it’s an app issue or just a lack of content on lemmy overall.

If you’re using Sync, it’s the three dots on any post or comment, then Filter. You can choose to filter (block) the user, the community, the linked website, or the entire instance hosting it.

Three dots usually indicate “options” or “settings” when using Android. I’d invite you to tap those buttons any time you see them and learn more about the tools you are using.