Of all the styluses I’ve tried, only the Apple Pencil has had the precision and reliabilty I’d consider for use in art apps. That said, it only works with the Pro modles, so it may not be an option for you.
YouTube has lots of art tutorials. Like “Draw with Jazza”. Tutorials specific to the app you decide to use may be harder to find. I recommend starting at the app developer’s site.
That said, I’m just a doodler. I play with a few apps and watch the occational tutorial; moslty for entertainment. I left my artistic ambitions behind when I figured out I’d have to work at it.