I don't really understand what you want. Can you show what exactly you can't do and what you want to get in the end? If you want your photo to fit in a frame according to the format, then you can contact the photographers. When photographers processing photos, they often do this. When I wanted to change the photo format to print it on canvas, I turned to
https://www.frameshop.com.au/canvas-prints. They changed the format and printed it on canvas. The result of the processing was high-quality. Now, when I need something like that, I turn to them.