Apparently, Prism Launcher chose to adhere to the idiotic principle of the hidden “trashbin”, .Trash-$(uid), invented by Ubuntu. Even though it’s based on QT. This can’t be disabled. It accumulated 139 GB of literal Trash, fully replaceable, over time. Just … why? There’s even an open issue about this, for over a year, referenced multiple times. I guess I have another point on my agenda.
Your desktop environment should have settings for when to clear the trash. You can also use autotrash to clear it automatically.
The Problem is: I don’t have a DE, and therefore didn’t realize programs would still try to use trashbins.