Hi,
I gave up on GRUB after experiencing an issue where it wouldn’t remember my last selection. That problem was resolved by switching to Limine.
I now use the Limine bootloader with multiple boots and BTRFS snapshot booting because it’s simple and works more reliable than GRUB. So far, I haven’t had any problems with it.
I’m not sure why Manjaro still relies on GRUB, given the many issues users have with it. But I suppose that’s just the way Manjaro does things.