As a photographer and AI enthusiast and technical artist I experimented everything possible long before midjourney and such came along (back in the days of discu diffusion in 2021). So I got a head start. Of course as a photographer I was very interested on how to use it for photography, and upscaling in this case. All commercial tools at this point suck for me.
But working with open source tools like comfyUI I finally managed to get something incredible. Example here : (first is 100% crop of tohe eye in the last image, second is upscaled version of the eye and then zoom out to original).