I think thus may be a youtube question more than a Firefox question but I just noticed it after upgrading to Firefox 104 on my PC.
I am going to youtube and am not logged into any Google products. Most of the videos I play on youtube start with subtitles enabled. I can of course go to the menu and disable them. I would suspect that if I logged into youtube I could probably set a preference that would stick, but I dont want to log into (stay logged into) any google stuff.
Is there a way to start videos without being logged in with subtitles OFF?