I have some experience with rpm-based systems. Why does dnf select the i686 architecture in the first place? On Debian based systems, apt selects the original architecture of the system by default.

Andrew, I think the spec file should be architecture agnostic. Otherwise I'll have to patch it when I add i686 or arm64 builder.

Thanks for everybody's feedback.  Just guessing, but I suspect the root cause is that another partition had Debian 32-bit Bullseye installed first and created the initial GRUB.  But moving on to catch up on other email.