I figured it out, it was part of the Steam app. You need to remove it from there. In the end it was not fully downloaded so it didn't take up 20+ GB but only a few MB. So I guess this estimation is not always entirely accurate. Stay safe everyone
Most apps like that do the registration server side and you would need To erase the device entirely and not use the same Game Center account.
Deleting the app does delete all data unless it’s designed specially and in that case, you need to know exactly what bundle and delete the data from iCloud on a mac, not from iOS.
In general, deleting the app ...