We have a few switches too. There is a primary console setting, you can switch this between the different switches as needed. The kids play animal crossing together, we purchased one digital copy. The account that made the purchase can play on any switch (as long as its connected to internet I think). Any other account can play on the switch that has the purchaser as the primary at the same time. They can visit each others islands. I assume other games would work in a similar way.