i exported the shotcut .mlt file to a youtube .mp4 file. but when i opened the video, the whole thing was blank. Bear in mind, this is a gaming video, but everything was blank. only the audio appeared
Did you select the option for Hardware Encoding on the export? If so try switching it off.
You did not say what you “opened the video” with. That helps. If you tried to export at 100% you will have this problem as already reported frequently here and explained why that is bad.