Once upon a time, Chris Murphy lists@colorremedies.com said:
a. Fix GRUB by giving it the ability to modify UEFI NRAM "bootnext" value, so that instead of chainloading the Windows bootloader from GRUB, GRUB will modify the system NVRAM such that the next boot (only) will directly boot the Windows bootloader. Thus far there's no interest by GRUB upstream. Whereas systemd-boot has implemented it.
Is GRUB upstream any more active these days? IIRC Fedora has a whole pile of patches; I'm sure nobody wants the pile to grow, but it doesn't look like that's changing. Could this be implemented in Fedora's GRUB?