on an unrelated note, I had no idea that Safari supports 4K videos in YouTube (let alone HDR) -- I switched to Chrome permanently after buying an iMac Pro back in the fall of 2018 bc Safari did mnot support 4K in YouTube, and I haven't looked back.
it is only due to this thread that that I now learned that Safari now supports 4K content!
I just might have to switch back, I generally preferred safari to chorme back in the day.