Ideally, you want to pick a VPN server that’s close to the Warzone 2 data center you’ll be playing on, and the game has data centers all over the world. If you’re playing in England, pick a VPN server in London. If you’re playing in the US, there are several Warzone 2 data centers all over the country, so double check which one you’re connecting to, and pick a VPN server in the same city.