You still have an extra partition, and there just plain aren't any bootloaders that can load those filesystems. You'd pretty much be stuck with ext4 as your mos

You still have an extra partition, and there just plain aren't any bootloaders that can load those filesystems. You'd pretty much be stuck with ext4 as your most modern filesystem option. Really the kernel should have a better system for loading firmware from the root drive after the bool state that the root drive becomes accessible. Not for everything of course, but many of the biggest firmware blobs are fine as late loaders