Tips for Enhancing Old Images for Large-Scale Printing

I have a set of old images (example below) that I need to print on structures with a height of 4 meters. I’ve cropped these images using Photoshop, and now I want to use Gigapixel to enhance their quality. I’m not expecting miracles, but are there any specific settings or tips I should follow to achieve the best results? I’m using the latest version of Gigapixel and have access to an RTX 4090 (24GB).
Any tips would be greatly appreciated!