Which Pokemon switch game for 7 year old

My SOs nephew is wanting a Pokemon game for his switch. According to his grandmother he wants Pokemon go for him and his sister to play. Pretty sure Pokemon go is just the app. Doing a little research there is Pokemon let's go for the switch and it does have co op that him and his older sister can play together. But it also seems like these might be a little more complicated since it's a remake of the older games.

I don't know very much about modern Pokemon. Haven't played since GB Color days. Which should we reccomend they get?

Pokemon let's go or just go for sword and shield or is there another I am not aware of?

I started with Blue when I was around their age, so I'll say either Sword or Shield for the sake of starting with a more traditional Pokemon experience in order to establish the basic rule sets and mechanics. But, they might get more out of Let's Go Pikachu and/or Eevee if they're already playing Pokemon Go and can mess around with the connectivity between the two.

You can't really seem to go wrong either way.

Pokemon Let's go Pikachu and Let's go Eevee are remakes of the first Pokemon game with rules that are much simplified from the current gen games (sword & shield). If this is your nephew's first experience with playing pokemon, or playing an RPG, I think the Let's go games are the better choice here.

That being said, Sword and Shield aren't that complex that a kid can't just go in and have fun with it anyway, but online connectivity is a big part of those games, so that might be another thing to consider.

I don't think you can go wrong here. Pokemon Sword and Shield are pretty simple as others have noted above.

The Let's Go games are even easier and have co-op though and the catching mechanic is similar to that of the phone app except that you use the motion of the controller to throw a ball instead swiping the screen.

If you're set on nephew sharing with his sister then Let's Go would edge out Sw/Sh I suppose since it actually has co-op but outside of that they're both good entry points for a seven year old.

I think every mainline Pokemon is pretty much designed to be someone's first Pokemon

I think either is fine (so whichever you can get cheapest)