My lecturer always used Photoshop for illustration and Krita for animation.
Krita is free and open source, so learning animation is great, yet the shortcut is different than CSP or Photoshop.
Paint Tool SAI is great software for illustrators. The brush is easy to modify, and the UI is easy to adapt.
If you prefer to go in a cartoon style and not use an iPad, you can use Toon Boom. Toon Boom is a standard industry software for cartoon animation studios. The tweening and rigging are more expanded and complex. Most Disney animated series or other cartoon series use Toon Boom.
If you want to try how Ghibli uses digital painting or animation, you can try OpenToonz. It's an open-source software, and it's based on the software Ghibli used, ToonZ. The best feature of this software is recognizing the line of a sketch. Basically, you have a sketch on paper, and you scan it. This software can recognize the line of it and immediately make a trace layer, so you don't need to trace by yourself.
Most of my friends used CSP. The brush, the store, the animation, etc., are great. Even though they started to learn how to animate with Krita, when we started to produce something, we used CSP as standard.