> But I imagine with Windows 11 around the corner requiring TPMs (which might require emulation on older hardware that doesn't have it) and secureboot, UEFI firmware emulators with these feature will probably get more popular and more accessible.

Unfortunately, there's no appetite - there's no point since that in a significant break Windows 11 only runs on new processors that happens to have both UEFI and TPM (not always enabled by default but it's there).