> I don't really care what Apple does on this regard, they were always doing things differently. IIRC, even Macs that supported EFI, only supported EFI 1.1, not 2.0, no?

Yup, but as long as you got an original Apple GPU that's enough to just stick a Windows or Linux USB stick and you can install straight from the stick. "Normal" PCI GPUs have to be reflashed with a GOP blob [1] so that Apple's EFI implementation can work with it.

Personally, I just went and installed OpenCore once and that's it.

[1] https://github.com/acidanthera/OpenCorePkg/tree/master/Stagi...