Definitely. Any artist can, no matter if they’re professionals, amateurs, do it as a job, or do it as a hobby.
My opinion is that if you’re feeling unmotivated, try drawing something completely new. I remember feeling very unmotivated before because I just kept trying to accomplish drawing these cool characters, but it didn’t work out the way I liked it. I then found other characters to draw (simpler ones), and I started enjoying drawing again. I feel like it’s because:
a) I kind of tried a different approach, and that different approach felt more exciting rather than this same approach I had before.
b) Because I went a step backwards by drawing more simpler characters, I was able to not only practice sketching/coloring, but I was able to achieve better results than I would if I attempted to draw the cool characters right away. As I kept achieving the results I wanted, I became motivated again to continue trying to draw cool characters again.
As for criticism, as stupid as this sounds, but for every criticism I receive, I try to tell myself something good in my head about my artwork. Like for example, if someone tells me that my anatomy is off, I acknowledge that that’s something I have to work on, but I also tell myself…let’s see…that my coloring looked cool! That way I don’t only focus on the negatives.