Video timeline previews force on/off on all web pages

YouTube has got nice feature to see previews in video time line and some web pages. Would be nice if that feature will be possible to forcefully turn on or off on all videos on all web pages.
( Maybe in brave://flags)
Because some pages not having that function. For example Infowars.
I remember it was available that function but gone. Some videos are long and is hard to find the exact moment.

Regard Rob