Well that would likely be your issue then. Garuda and it's snapshot features are only going to work if you install using btrfs.
It's not that you can't install using ext4, but the Devs have made it clear that if you choose to do this you're on your own. Garuda is designed for all editions to be installed on the btrfs file system.
Other install methods are neither supported, nor recommended. If you wish to set up your system in this manner please solicit advice elsewhere than our forum.
All our editions use btrfs and a custom version of grub to enable recovering from a system breakage by simply rolling back to an earlier state via timeshift at the grub boot menu.
Likewise, Garuda is not recommended to be installed in a VM as our distro is optimized for a bare metal install. Neither of the methods you are attempting use are supported by Garuda. It is simply a waste of forum support resources to respond to issues that we have advised to not be used.
As the forum is intended to be used as the primary reference source for information for all those new to Garuda we really don't want information that conflicts with the standard recommended methods posted here. For simplicity of support the information on the forum is intended to be applicable to all our editions when new users are searching for a solution.
If you want to install Garuda with with Windows, Apple, and a half dozen other distros all running different file systems with different boot loaders fill your boots. However, we can not provide support for non-standard installation methods on the forum. It only serves to confuse newbs and creates a support nightmare.
Posting this type of conflicting information on our forum only serves to confuse newbs. The advice on our forum should of a consistant nature so that newbs can easily search and find a solution for their installation issue.
If you had installed in the standard recommended manner you would not have recieved that error. Continuing with this post only serves to further muddy the information we want newbs to be able to access to fix their install issues.
Sorry, but further discussion on this topic is counterproductive to what we are hoping to achieve with our forum. The advice on the forum needs to be applicable to fixing problems with the standard Garuda default installation that is recommended. Half the problems relating to a new installation are because users want to deviate from the recommended method.
Regrettably, I am going to have to close or delete all posts requesting this information from now on. Otherwise our forum is going to be filled with mostly information that is not applicable to all our standard editions. This situation has to be remedied and the only way to do that is to put the food down on it now before it gets out of control.
My apologies, but case closed. This is not a use case we support.