…it shouldn’t be visible in the overview of subforums imo.
I’ve muted so many threads that are a tar pit of negativity and nihilism but they all pop up when you go to community.drownedinsound.com and only disappear when you actually go into the subforum itself.
I don’t think there’s a setting for that, but it sounds like a great bug report to share on meta.discourse.org. It would make a lot of sense to respect the muted state of a topic on the Categories screen.