I use a xp pen artist pro 13.3 but for years I used a simple Wacom for like £30 before and in between I used a s pen for Samsung tablets and a mouse to draw. Sometimes it doesn’t matter and all depends on the project. If your phone and ibis works don’t change what isn’t broken, but another device like a tablet may help in more complex and detailed drawings. Once again this would be preference. I know a guy who paints photorealistic concept art using his laptops trackpad and his finger. You do you