Why does iMovie crop a video and when the video is set to fit, it adds black space both sides?

I have a video that I recorded with QuickTime Player on my MacBook Pro M2 with Apple Silicon. When I imported the video into iMovie, I noticed that my video was cropped at the top and bottom when the cropping was set to "crop to fill." I decided to change the cropping option to "fit," but instead of my original movie file filling the screen, iMovie added black spaces on the left and right, making the video fit the screen rather than fill it. This is very unusual, as other video editors don't behave like that with the same video. Is there an option to export the video as it is without adding black spaces on the left and right? I don't want my videos cropped but I want them to fill the screen as they are. Attached is the screenshot below;

1. First image has cropping set to crop to Fill and it cropped out my video's most important areas, top & bottom.
2. Second image has cropping set to fit and it added two black spaces on both left and right instead of filling the file but fits the original video.

I suggest there should be an option of free hand cropping tool to select the size of the video that we want or make option of Fit to actually fill the screen instead of adding two black spaces on the left and right. It's weird but iMovie is such a fantastic tool. Video export is pretty fast as compared to other video editors. We just need this feature to make the app complete.