Yes and no Stadia has hardware in data centre's all over the world and you connect to your local centre, Destiny 2's main servers are at Bungie's data centre's and during pvp/pve the data the client is sending gets relayed through them so doesn't really matter if you have 2 clients on the same network it doesn't improve latency. loading times or anything really, there is some old video's on youtube where the guy goes over how Destiny's 2 servers are setup its an interesting watch.