Hi there, here's a step by step youtube video on how to do it! https://www.youtube.com/watch?v=p1yGu2Bbwxg
Several have done this on Hometalk- https://www.hometalk.com/search/posts?filter=painting%20leather%20sofa
You can paint it with Amy Howard products https://www.sincerelysarad.com/amy-howard-one-step-paint-tutorial/
Leather need to "breathe". It is a natural material. Will probably peel if painted.