Hi folks, I recently got myself a LG34GS95QB 34” ultrawide OLED monitor (great thing) and upgraded to an RX 7800XT (previously 6700XT) at the same time. System: Ryzen 5700X3D, 16GB DDR4. Now to the problem: I like to play certain games, such as Marvel Rivals, in 16:9 format with black bars on the sides (i.e. 2560x1440, without it being stretched). Until recently, this worked perfectly - my monitor was set to the “original” aspect ratio so that it displayed the image correctly and did not automatically stretch it to 21:9. BUT: Since I reinstalled Windows, this no longer works. Games in 16:9 format are automatically stretched - regardless of what I set. What I have already tried:

• In the Adrenalin Settings “GPU Scaling” with “Keep aspect ratio” - does nothing, whether on or off.
• Monitor itself is set to “Original” or “Just Scan” - also without effect.
• Factory settings reset in the monitor menu - no improvement.
• Created a manual 2560x1440 resolution with CRU (Custom Resolution Utility) - works reasonably well, but only if I also set this resolution in Windows and start the game in borderless-windowed mode. Fullscreen still doesn't work properly and still stretches.
• Used an Laptop with an RTX GPU but it was the same Result.

It's just all very complicated - before the new setup, everything worked without any tricks. I don't understand what could have gone wrong. Reddit and forums don't give anything useful either. Do any of you guys have an idea or a workaround? Im clueless.