How to uninstall deleted game?

I'm gonna be direct here, I got a game through non conventional ways, got it installed, game worked but crashed because my system is trash, forgot to uninstall it before permanently deleting the game, now, it sits there, occupying 25gb of space without doing nothing, and I can't delete it because it doesn't exist-ish.

I know it was a stupid move, I know this is idiotic, but I really need help and would be very happy if someone here could give me a heads up on how to solve this.