How is big sur able to run on ryzen/intel machines?

My cousin told me he made a ryzen Big Sur Hackintosh, and I was like

No that's impossible, since Big Sur is ARM only, and ryzen is X86.

I read up on it and apparently it is possible, but I'm still trying to understand how.

Is it emulation of ARM on X86? or am I understanding the difference between X86 and ARM wrong?

Author: @slimeblue1123