Did not work on mobile. Still showed in recommended videos under the current video and on the main homepage.

Edit: Just refreshing wasn't working. Or straight up closing and reopening the tab. So I removed the extension, closed all open youtube tabs, went to settings to delete my cookies and browsing data, then reapplied th extension and went on YT again. It didn't do anything as a guest, but it did remove shorts from my homepage and under the current video playing when I logged into my account. It still showed the shorts when performing a search, though.