Image Banner Section-Desktop Image & Mobile Image Sizing Adjustment

I am able to upload a desktop image, and mobile images to the section called “image_banner” Dawn 10.0 theme. The automatic feature for image sizes (adjust to 1st image, small, medium, large) does not work for my case. My PC image will always be 1600x619 and mobile 800x1279, meaning the PC image is on the smaller side, and mobile is large. How can I make it so the images actually populate how I want them?

Essentially the desktop image I want-"object fit=cover/min height 460 max 800

Mobile Image I want-"object fit=cover/min height 550

I got the sizing from a site I like how the banners look, can someone help with that please? Also, if I choose container on mobile, is there a way to get it on top, rather than bottom of the banner?

Thanks so much!