I didn’t like it either.
Maybe the reason that people jump over to substance painter.
But to challenge myself, I used it a lot recently. Yes it can be slow. Yes it can be annoying.
But practicing helps. Point is in these courses, texture painting has low attention here. Very superficial.
And also I can not find very good tutorials online. But what I found plus some new challenges (do this in texture paint). I still not like it very much. But my annoyances with the tool is gone.
And the process is better than, going back to GIMP. So it’s a process of learning!
It has the same annoyance level, for me, with sculpting. Seeing lot’s of people doing really nice projects. But for me, it’s hell. If it’s your first or second try, don’t give up. Try to think the bender way!
And it needs as much time as you did spend on modeling meshes.
Everything in Blender takes time to learn. There is nothing at Blender where you can say, after a week I’ve learned it all!