Cannot force resolution to 1280x800, always defaults back to 16:9 aspect ratio

[Baronfuming]

Hello,

I have a bit of an edge-case here. I want to play Kingmaker on my Steam Deck, but streamed through Steam Link from my PC. This way I can have better battery life and higher graphics settings than if the game was running from the deck itself.

The only problem is that when I launch the game on my PC, it does not give me the option in the graphics settings to change the resolution to 1280x800. The closest option available is 1280x720, which will result in some black borders on the top and bottom.

I suspect this is because it detects that I have a 16:9 aspect ratio display, so it automatically hides 16:10 resolutions. Testing this game running from the deck results in the 1280x800 as the default resolution, so the game is certainly capable of it.

I have tried the following:
Opening the Registry Editor and navigating to Computer\HKEY_CURRENT_USER\SOFTWARE\Owlcat Games\Pathfinder Kingmaker
From there, I modified the following entries to these decimal values:

Screenmanager Resolution Height_h2627697771 = 800
Screenmanager Resolution Use Native_h1405027254 = 0
Screenmanager Resolution Width_h182942802 = 1280

This seems promising, but the settings revert to the default 16:9 resolutions when the game loads to the main menu.

I have also tried setting the game's entry in my Nivida Geforce software to 1280x800 resolution, but it also reverts once the game starts.

Does anyone have any tips or useful launch options to prevent my game from insisting on 16:9 aspect ratio?

Edit: A workaround is going into the Nvidia Control Panel, and making sure DSR (Dynamic Super-Resolution) is off in the 3D settings, and then manually forcing my display to 1280x800.
This results in Kingmaker defaulting to 1280x800. This solution is awkward though, since I will have to manually change the resolution back and forth depending on when I am playing.

If someone has any better ideas, please let me know.