They were very lazy with this game. If you're a Pokemon fan, you'll have lots of fun playing it, which I did, but that's because it's literally just a reskin of Diamond and Pearl. In the Ruby Sapphire remakes, they actually added new things, like incorporating mega evolutions into the story, but you'll get nothing like that from this game. There's so much they could have done: maybe Sinnoh variants of gen 5+ Pokemon? The dynamax at least? But you get nothing new. They didn't even add the ability to use the Switch's touchscreen during battles.
Once again, I had fun playing it, but that's just because Diamond and Pearl were really good games. If you're a Pokemon fan, I'd still pick it up, but wait for a sale because it is not worth $60 no matter how you look at it.