LogFAQs > #977335986

Kaldrenthebold posted...

https://www.androidauthority.com/youtube-reportedly-slowing-down-videos-firefox-3387206/

these are the important parts:

Redditor vk6_ has shared a video showing a five-second delay when loading into a YouTube video on Mozilla Firefox. Upon manually changing the user agent on the browser to Chrome, the five-second delay no longer appears. The video has been reproduced below:

Google is targeting useragent-string (or maybe not, according to the reddit nerds), so there's a fairly-trivial workaround of messing with the browser's reported useragent.

However, multiple users have reported the same across Firefox and Edge. The users claim to have experienced the delay without any extensions enabled, indicating that the delay could be on a per-account basis. The delay also does not trigger just once; it is reportedly triggered every time YouTube links are opened in a new tab.

Or, an even more trivial workaround of just not logging into youtube, which seems to also help hose the anti-adblock mechanism.