Re: Resolution issues
I found a similar issue when trying to implement virtual super resolution; the higher resolutions were in the dropdown list, but when I picked them, they would not apply. However, I did find a workaround.
If you open the GamerSettings file (with Notepad) in your game installation (\Origin Games\Mass Effect Legendary Edition\Game\ME1\BioGame\Config), you can adjust the resolution there. It stuck for me, but if you adjust from the dropdown in-game after that, you'll need to edit the file again if you want to use the higher resolution.