I've just bought this game for the purpose of playing it together with my wife(this is our first game of the series).
Hosting a split screen game in offline mode, waiting for the world to load for X minutes while look at this prompting message: "Connecting..."
When playing solo offline, the game loads immediately without a problem.
Variables:
I created a world first in single player. Played it until my character dies.
Both accounts we're logged-in into PSN(both accounts doesn't have PS+ subscription).
Accounts have different region one for R1 and one for R3.
I use the R1 account to buy the game.
I've already activated the PS4 as the primary.