Correct. But Windows is not changing the BIOS boot order. It will however change your EFI to make itself the default boot again, even if you configured it to use a separate ESP on a completely separate disk and the boot menu residing there. That’s by design as you can access your efi settings from a running system via software, while your chances to change your BIOS settings from outside the BIOS are slim to non-existent.
Also every BIOS not decades old can indead run with a hybrid setup of GPT formated disk with a small partiton to replace the MBR functionality.
Correct. But Windows is not changing the BIOS boot order. It will however change your EFI to make itself the default boot again, even if you configured it to use a separate ESP on a completely separate disk and the boot menu residing there. That’s by design as you can access your efi settings from a running system via software, while your chances to change your BIOS settings from outside the BIOS are slim to non-existent.
Also every BIOS not decades old can indead run with a hybrid setup of GPT formated disk with a small partiton to replace the MBR functionality.