[2022] Can't get rid of dead CK3 mods from the PDX Launcher

It's not actually deleted, the creator has changed the visibility to hidden, that's why it keeps getting installed. You'll need to manually delete it in your subscribed mods and whilst I think you're pretty well versed in how to do that I've included a link: https://www.wikihow.com/Delete-Steam-Workshop-Mods