At the time of writing the GNOME edition of garuda uses GDM out of the box which has issues with Optimus-Manager.
If you run Optimus-Manager you get the following error message:
"ERROR: a GPU setup was initiated but Xorg post-start hook did not run.
Log at /var/log/optimus-manager/switch/switch-20220524T150946.log
If your login manager is GDM, make sure to follow those instructions:
If your display manager is neither GDM, SDDM nor LightDM, or if you don't use one, read the wiki:
Cannot execute command because of previous errors."
It can easily be fixed by changing the default login manager to GDM-Prime, instructions for which can be found on Optimus-Manager's git GitHub - Askannz/optimus-manager: A Linux program to handle GPU switching on Optimus laptops.
It was a pretty simple fix but considering Optimus-Manager is installed out of the box it would be nice if it just worked rather then required users to install a patched login manager.
Also, for any users reading I highly recommend installing gpu profile selector which adds an easy to use GUI for changing modes (you may also need to install envycontrol).