Is it possible to print larger photos from an iPhone XS?

I’m a painter and know little about photography. I have some beautiful photos that I would like to copyright and blow up. I understand that with this iphone xs and the pixels I can only print smaller photos. With an APP like Remini would I be able to print images larger! Would love to make one 30”x40” perhaps a giclee or on metal but I read the resolution would be awful. And also that the APPs change the photos. Has anyone come up with a solution for this. It’s a photo in nature but almost looks like an abstract painting.