Great to hear that you’re looking to get into PostmarketOS development! I recommend taking a phone that’s already supported, using it and then figure out how improve support the device.
Porting/Mainlining a new device is also possible but that can be demotivating if it doesn’t work and it’s generally harder to get started with.
If you have any questions or need help you can dm me and I can help.
Nen Bürgerbegehren wär wichtiger
Not sure. You could try running it in Valve’s gamescope compositor. Maybe the game only supports that low resolution