And another UEFI gpu on that pos chinese motherboard works in Legacy or UEFI?
Other options, flash a more recent vbios from XFX or AMD, look in TPU db.
If the card is need to boot in UEFI mode, can try to update GOP driver, here:
https://winraid.level1techs.com/t/amd-and-nvidia-gop-update-no-requests-diy
Other than that, pack it all nicely and send it to the Chinese.