Do you play the same games together often? In that case unless it is a couch co-op game (some are) you would need a second switch with the same game.

You can have multiple profiles on a switch and can share games between profiles on that switch. If it’s physical you can just play that game on any switch on any profile (just whoever has the cartridge). If it’s digital, if you buy it on the primary profile of a certain switch (make sure you do this) then all the other profiles on that switch can play that game too. If you want to share digital games between different switches it’s more complicated, but it requires cloud syncing and some other shenanigans I couldn’t explain.

They are all portable but you might be talking about the switch light which doesn’t have removable controllers. If you have a tv one for everyone, the you either need the controllers from the other switches or extra controllers (joy con style or normal controller style) to play together. Some games can be a lot of fun to play on the tv together. Check how many people a game can play.

I hope I answers some of your questions.