When I first began digital painting, I tried the program Painter. I know there are many digital artists who use and like that program, but I never did get the hang of it, and I thought that, compared to Photoshop, it crashed an awful lot. So i decided to put my effort into learning how to paint with Photoshop. This was around the time that Photoshop had upped its game on the painting front, and had come out with the mixer brush. This brush allows one to mix pixels from an underlying layer in a myriad of ways. With it you can mix underlying pixels with new paint or with nothing at all in a variety of styles and ways. The possibilities are endless.
So I concentrated my efforts on learning to use the mixer brush in Photoshop. By this time, I had acquired a Wacom graphics tablet, and was using a pressure sensitive stylus for my painting. For those who don't know what this is, it looks like a pen, and when applied to the graphics tablet (while using a brush or other tool in Photoshop), it makes marks on the computer screen. So it is not quite the same as actually painting on a paper because your hand and stylus are not on the screen, but on the graphics tablet, while your image and paint strokes are showing up on the computer screen.
I used Photoshop and my Wacom tablet to create digital paintings for a number of years, and all my earlier paintings were created that way, but last Christmas I received an IPad Pro and an Apple Pencil. This enabled me to start using an IPad app called Procreate. Procreate is a painting and drawing program that lets me paint with the Apple Pencil directly on the screen of my IPad. It also allows me a lot of freedom in turning and resizing the canvas just by using finger gestures. Procreate is a very powerful and intuitive app, and I now have switched to using it for all my digital painting. Now when I try to use Photoshop to paint, it seems very cumbersome and unwieldy. I still use Photoshop to get images ready to paint, and I often use it on images I have already painted, but I no longer use it for painting.