might be possible to use seabios as a UEFI boot and have it act as a bios (as it is a bios “emulator”), never been down that rabbit hole, but perhaps there is someone who has if you search / ask around

Git repo of seabios: github.com/coreboot/seabios/tree/master

not sure if it will work, just hit me when I read this. anyways, good luck, hope you get it sorted/working 🙂