How aspect ratio scenes?

hi , in gdevelop we can aspect the ratio of windows and not scene so if our scene be 16:9 , a 4:3 or 21:9 monitor can`t run game and it will be stretch . any idea to fix it ?

I’m not sure I understand you, but I will try an answer.
When you switch to fullscreen, you can choose to keep the aspect ratio or not.
If you don’t keep it, the game will stretch. If you keep it, you will see black bars on the edges.

How to make it not stretch?