I 300% think this too. Like he somehow goes to the ocean and gets on a boat and reaches different continents you can't see as the player.Lore wise? To other foreign lands & worlds. Likely another place similar, in a lot of ways to Terraria, but with an "Asian" aesthetic. He already sales the Dynasty Wood sets, which are impossible to get in-game without buying them from him & he'll also have Bamboo sets, which kinda confirms this theory. I'm sure he goes to quite a LOT of different places, but I'm pretty certain about the "Asian-themed" worlds.
This was the same theory I had about Terraria: Otherworld! I suspected, this is what the major selling point of the game was, along with a few other features!Reminds me of an idea someone had for post-ML content where you go to the ocean and just travel to another whole different world from your world.