There are two ways to do this.
One is to set the size of the GUI smaller from the settings field.
The other is to bring up the development console and type "//maincamera>camera.setdepth 10". To restore the original settings, type "//maincamera>camera.setdepth 1".
And for the development console, please refer to this page.
Question, I’m gonna assume you do all your videos on pc? You never show any of the controls and it still looks good and uncropped so idk