I bought the game for my 6 year old son. Its the one game he wanted more than any other on the switch. We went with the digital code because there are no cartridges to break/lose (our oldest broke his Nintendo 2ds a couple days after he got it because of the cartridge issue, wasnt chancing it).
He absolutely loves it. Its challenging for him, but not impossible. I can hear him getting mad at something, working out how to beat it, and being so proud/happy/excited when he does. What makes it better is that he does it on his own. He doesnt feel so overwhelmed that he has to ask for help.
I cant tell you from a personal standpoint what the game is like, or even about. I can tell you my 6 year old loves it. Preferred it to Yoshis Crafted world and others.