What I suggest you could do is:
- chroot into your system with a live USB, either using the relevant tool in the Garuda Welcome or with this manual procedure https://forum.garudalinux.org/t/how-to-chroot-garuda-linux/4004 (only the initial part where you chroot into the system, not the grub installation).
- from inside the chroot, get and provide your garuda-inxi
and perform a garuda-update. This might solve possible problems in your previous update, but will also install the recently downgraded grub version from our repo. - to be honest, I don't know if reinstalling the grub into your system (the second part of the tutorial, or also with the tools in the iso) would be necessary at that point, I guess so, but you anyway could try exiting the chroot and rebooting normal before, to see if you have any positive effects. If not, repeat the procedure to install the grub in your system.