Decent watch, probably won't watch again, but can recommend, especially for Rock fans.
I've fantasized about Dwayne Johnson in a tutu as much as the next guy, but this is kind of the movie equivalent of when the Rock went heel in the WWE (WWF at the time). He's playing an obnoxious, borderline MEAN, character who isn't all that smart (basically a dumb jock type) , and while the movie is about redeeming the character it is hard for the character to be redeemed.
It's just awkward, he normally plays smart capable roles where he is likeable, as Dwayne is naturally on-camera-likeable, so making him a jerk is hard, and they overcompensate. You seem something closer to what they should have done in "The Pacifier" where Vin Diesel is rough but well intended, and you can see elements of that in this, but he just goes full jerk.
I have a lot of issues with it being common practice to lie to children (which we teach them to be wary of when strangers do it), but digressing.
I have all sorts of issues with the logistics of a world where this type of tooth fairy exists, not to mention the other things they mention existing. It's not too far off from the "Santa Claus' sleigh flys by christmas cheer", so there is a theoretical version of "The Santa Claus" in here somewhere.
So the movie doesn't make sense a lot, but it's a kids movie: which would be fine, but it wildly goes back and forth between goofy antics that should almost only make kids laugh, and high concept business jokes.
I think this movie tried to do too many things and ended up getting some of the fundamental things wrong.
It's not a terrible movie, and it's probably better for a younger audience, but I don't think it's a good movie, and there are a lot of other movies, even just ones with Dwayne Johnson to watch.