Hello!
You posted This helping someone in 2019 and it helped me solve a propblem ive been trying to solve for days. I found it and it worked for my resolution lock. Thanks for the help!

"Alt + Enter didn't work for me, but I managed to figure out a way.

I pushed all the function keys to see if there was a settings hotkey, there isn't as far as my >1hr gametime can tell, but F11 windowed the game and I was able to navigate into the video settings from there and pick my resolution.

Hope that helped."