Hm. I can’t think of why a save file issue would cause this, because it’s only plucked to populate your gold amount, the items on your shelf, and a couple very spesific things. And both itch and Steam use the same save files.
But it’s at “C:\Users\YourUserName\AppData\Roaming\Godot\app_userdata\OnePotionPlease” The numbered savegame files are for each day.