For anyone wondering how to do this: r.Upscale.Quality=0 will set the upscaler to nearest neighbor. r.ScreenPercentage can be used to reduce the resolution before upscaling is applied. Together, you should be able to get a nice pixelized look. Don’t forget to disable all the graphics features you don’t need anymore and place these commands in the engine INI if you want them to run on launch.
For some reason r.Upscale.Quality=0 still blurs the pixels by using bilinear interpolation when upscaling on mobile renderers. No clue why and it’s causing some frustration to say the least.