When working in Shotcut, you are always working within the confines of the Video Mode. The Video Mode is like a canvas to a painting. You can check your Video Mode settings, by clicking on Output in the Timeline, and then clicking on Properties.
If your source resolution is 1280x720, your Video Mode might be the same resolution depending upon the steps you took.
So if your Video Mode resolution is 1280x720, and your source is the same resolution of 1280x720, you would use the Size, Position & Rotate filter. Use the scroll wheel on the zoom, and you can also use the scroll wheel on the Position locations.
Export without changing anything in Export → Advanced.