I found something that’s not a full solution, but it is a quick fix. Go to the test tab, then set the device to 1920x1080 desktop. Make sure the scaling is set to Actual Resolution, then open OBS Studio. Make a new Game Capture in the Sources section (not Window Capture, as that captures Studio itself instead of the preview.) Set the game capture to capture Studio and you now have a preview of your game, even if it is cut off in Studio. If it is too big or too small in OBS, right click in the preview area and select Resize Output (Source Size) to set the preview’s size to Studio’s preview size. To have a fullscreen preview (which is where this method really shines,) right click and select Fullscreen Projector (Source), and select your monitor. You now have a full-size, full-resolution preview of your game, and you can even move around by using the cut-off part of your game in Studio on another monitor.
In Studio
In OBS
