Server? Like, a Discord server or just an online community? The only community I know of is MKBoards, but I wouldn’t recommend it if you’re looking for casual play. That site is way too competitive for my taste.
Alternatively, you can hop in worldwide races or battles. They’ll pair you with people close to you in terms of VR/BR respectively. Thats mainly what I do. Mario Kart 8 Deluxe is the game I’m playing right now and I enjoy it without being part of a community or clan.
The only community I know of is MKBoards, but I wouldn’t recommend it if you’re looking for casual play. That site is way too competitive for my taste.
...and MKBoards has already been discontinued anyway. I looked it up and can't access the link or anything. I did find an alternative called MKCentral though.