It can be a real nuisance sometimes when I start a new character just to bug test some things I think might not be working, then have to close the game and re-open it so I didn’t screw up the map or give an unfair advantage by things I spawned just to test out. I think an option to quit without saving would be really nice
there is already: Debug menu>Q
You can always terminate the game process too. It’s what I do in case something happens.
Press the home button on android.
It even works before I watch the last moments of my character’s life.
Edit: But then I’m sure you play on a Laptop or PC.
As people have pointed out, there are ways to do this, but none of them are officially supported and they can break your game. If you want to do this safely you need to back up your save file before you start.