Update -- problem fixed! No wonder there were no fixes to be found. Somehow, he apparently managed to delete his C:/Users/[user] file?? And, it got replaced with a new (likely default) folder with the same functionality simply titled "user". So, the previous C:/~/[user] file that itch was attempting to put its games into no longer existed, therefore causing the error where it couldn't read the space properly. I... have no idea how that happened, honestly, and I was pretty baffled. Maybe this'll help someone else who has this issue in the future? Or, maybe this was just some kind of blue-moon cryptid situation where it's unlikely to ever happen again. Still documenting what worked just in case!