On Windows I don’t use the “My Documents” folder. This allows me to back up the partition that has user home folders without it being ballooned by game install files and game related data.
I’ve intentionally installed Steam, Lutris, and their games outside of the user home partition/folder structure.
I completely forgot about the /GDStash is in the user home folder as in “/home/ghoultek/GDStash”.
Ah you solved it!!! Now I see why the 10-8-2020 backup was over 900mb.