Hi there, welcome to the forum.
For sure your home partition is not lost and you can reach those data.
The fact is that Garuda uses BTRFS subvolumes, and @home is one of them.
I think the topic has been discussed several times in the forum.
In my opinion the best solution is to just symlink your old home into your home subvolume, but there are several options possible, e.g. you could change your home to the old one changing the fstab.
See e.g.