Can't uninstall old copy of the game

So back in 2019 I had SoT on Gamepass, and since then I stopped playing it and it has remained installed, but invisible on one of my drives. I can't delete the old copy of the game, which sits and takes up 46gb on my harddrive. It doesn't appear in "Add/Remove Programs" in Windows. The Xbox app thing just tells me I don't own it, so I can't uninstall it there either. Windows wont let me just delete the files. I don't know what to do anymore, I want to free up the space but it's like the game is designed to not be removable.