Which multiplayer game should I buy? :o

(Before you read, excuse me for my english, it's not my first language D:)

I'm just waiting for my Switch (I buiied it with Zelda), but I was thinking that buy a cool multiplayer game for me and my friends would be nice.

The title I'm considering are:

Mario Kart 8 DX; Splatoon 2; Arms

But I have some problems with them D:

With Mario Kart 8 DX... well, I'm not really excited. I'm a semi-pro player here in Italy, and I won some competitions in my country, but... it's just another version of Mario Kart 8, that I've completed at 100% on my Wii U. It really worth the cost of the ride?

With Splatoon 2, the only real problem is that I shoud buy another couple of Joycon. I love Splatoon, the Salmon Coop mode it's really cool, but... yeah. 80€ of Joycon are really a turnoff.

With Arms, same issue of Splatoon 2. The Joycon price is just really high, so I must consider it.

Aaand that's it! Any of you have some advice for this doubtful player? ^^