AFAIK HDMI protects from direct ripping so how do they actually do it?

https://en.wikipedia.org/wiki/High-bandwidth_Digital_Content... You mean this? Doesn't sound that hard to bypass

I assume HDCP is the reason a lot of ripped content is not in 4K (or because needs a more expensive Netflix subscription). It sounds like people just bypass it by using an HDMI splitter however.

Very easy to remove it with an HDCP remover like HDFury, or even an HDCP downconverter and then using the known master keys to decrypt that.

Eh sort of sometimes maybe. Lots of hardware/cables out there that don’t care what you’re doing. I can use an ATEM mini to grab basically anything I want so long as I’m down to capture in real time.