I used manjaro when I first started, but have had mixed success since then. Some criticisms here about shipping broken userspace (at least with their mobile OS): https://drewdevault.com/2022/08/18/PINE64-let-us-down.html
But, ubuntu is great for beginners, and i've always had good success with debian, although I'd point beginners to find an installer with non-free firmware until you know what's going on
superuser.com/questions/469249/how-can-i-restore-grub-for-fedora ... maybe try rming that file, then /sbin/grub-install. All else fails, use package manager to purge and reinstall grub