I agree with your point about OP's statement regarding "where is not not needed Windows in any way, to the Remote Device Management baked into firmware as Apple does with its hardware" I also read that to mean that the firmware solution is self-contained and complete, even though that's pretty misaligned when you consider the meaning of a "remotely" managed device (remotely managed by what?).

But it's still entirely factual in my own description. When a device checks in during initial setup, the firmware-level boot process can receive policies that block alternative OS installation, and that absolutely is a feature of the firmware.

Anyway, I tried to interpret OP's meaning, and provided more detail on how Apple's firmware is special.