Setup classic youtube UI

Step one

Install a userscript manager,any will work but tamper monkey works best

Step two

Download the latest userscript from vorapis site

Step three

enable PLAYER_REFUSE_ALL_STATUS_WHEN_INTERCEPT_BORKING_POSSIBLE in V3 settings(note the settings menu has changed places a few times but its usually in the title bar somewhere)

changing this helps with firefox and ublock if it works fine without changing this setting then you can leave it alone