Each smartthings hub is assigned to one and only one shard. You will be allowed to log into the other shards, which is weird, but you won’t see any of your devices there.
I’m not sure what the confusion is with @yvesracine Ecobee instructions , but generally you need to install smart apps on the shard where your hub is assigned. Which will be different for different people. The one you mentioned, NA02, is the one that was typically assigned to new North American accounts established after November 2015. UK accounts and older North American accounts are on other shards.