Letterboxed when launched from Steam Game Mode

[needo37]

How to reproduce:

1. Install the GeForce Infinity flatpak on the latest version of Bazzite. (I am using a GPD WIN MINI 2024)
2. Launch GeForce Infinity in Game Mode

GeForce Infinity is squished into the center. It is not full screen. I have tried setting the application to use Default, Native and 1920x1080 display. Still squished into the middle.

Launching it in Desktop mode works fine.

[moust4ki]

I have a Legion go 2 with Bazzite: I am unable to use 1920x1200 resolution, in Bazzite (game mode) or desktop the game is locked to a 1920x1080 resolution (letterbox). If I force exclusive full screen in the game and set 1200p, the ui turn into a square resolution.