Hello, have you tried uninstalling the add-on, if yes does the video works on your side then ?
On my side with Firefox 152.0.1 (64 bits), the add-on does not block the video, I fail to reproduce your bug. Although when threads contains video I don't see the download buttons of the extension like it should. I will see if I can fix that this week, must have been a regression from newer Firefox or 4chan.