I've found a workaround for color glitches on fullscreen videos on Mac
Download and install Helium Browser https://apps.apple.com/us/app/helium/id1054607607 which is an always on top web browser (useful anyway for youtube videos).
Put the helium browser window in a corner so that you can barely see it at all.
So when you put a video on fullscreen the ...
The discrepancy exists because something/someone messed up handling of color spaces and/or color profiles.
A very short and crude explanation:
Colors on computers are expressed as numbers - for example here as RGB with each color ranging from 0 to 255 (i.e. 24 bit color).
Computer displays are not all alike - they can display different ranges of colors. ...
The Mac system color palettes are typically stored as "clut" resources in the ROM. There are palettes for 8-, 4-, 2- and 1-bit depths.
Belkadan Software has helpfully provided the 8-bit palette here: http://belkadan.com/blog/2018/01/Color-Palette-8/