How to change viewport in kmplayer?

Question

Software players

I am studying one course and faced the problem that the editor window does not take up enough space on the video, and my eyes get tired of this.

As a solution, I want to increase the screen viewport. It will be more convenient to save the enlarged viewport to one profile, and by default to another, so that you can easily return to it later.
I would be grateful for your advice, I've been struggling with this problem for several days. I have already used several players, but each had some kind of unsolvable problem, for example, increasing the speed without sound distortion.
Thanks in advance))