Just open an issue on the github suggesting the feature. You can also make a ko-fi donation as someone suggested. Doing something like that as straight-up paid work is legit, but it would cost a heck of a lot more than $20, as everyone has already said.
Start out using your phone. Get enough experience taking pictures that you have a better sense of what you might want in a camera that your phone doesn’t already do. Take at least a few hundred careful, thoughtful shots that way to see what it is that you can and can’t do with the phone. Then come back and discuss your findings in detail and we can make more suggestions.