TIL You can see all of the Lemmy community comments and posts that have been removed at the bottom of the sidebar.

It's called Modlog in the Monitoring Stats section.

I wasn't sure if my posts were being removed but it turned out to be some federation stuff. This way you can check if you've broke a rule or something.

Edit: If you don't see it, look in the about section of the community you're in, it might be there.