Windowed fullscreen is locked to whatever resolution your monitor is set in windows.
Fullscreen resolution is broken. Setting to 1080P or 720P has no effect. Game is still rendered at whatever resolution Windows is configured.
Configured at 4K your average Frame rate is around 15 fps, regardless if you set fullscreen resolution to 1080 or 720
Configured to 1080 your average Frame rate is around 50-60 regardless if you set your fullscreen resolution to 1080 or 720
Finally configured to 720 under windows, your framerate is around 110 fps, but it has constant visual glitches where the screen flashes.
If you need video proof I’ll be happy to record this behavior