Hi Bryan,
Ok let’s do this step by step, first of all, please remove this section right here this is an empty section, this will only put an unnecessary white space to your page (unless you are planning to put something in there).
Now on your banner section, please remove the negative margin and huge padding to that section, set it to 0. That is part of the reason why that section looks mess up on the mobile view. Apply the top and bottom padding to the ROW instead.
Now, let’s go to your section background-image, set your background-size to cover; that is because you need your background to cover your section all the time. That is the reason why we are seeing white space on the section, because your background-image did not cover it, and it only cover the center part of the section.
Another thing with the background-image is the position, by default background-position is set to center of the image (x and y axis). Most of the time this option gets overlook because the bg-image fits in desktop view, however, in mobile portrait view the image always gets cropped (imagine you’re trying to fit a landscape picture to a portrait frame), since the person on the image is not really in the center, we need to adjust the x-axis positioning so the person won’t get cropped, I think that is about 35% from the left, so your background-position should be 35% 50% that means 35% in x-axis and 50% in y-axis.
Hope that helps,
Cheers!