Can someone explain how im supposed to expand in Japan when the realm laws dont allow.

Like the title says. I just got the "new" dlc and am really struggling to make any progress in Japan. Every tutorial ive looked at in the past hour just says "switch to Soryo" but that does literally nothing when the realm law dissalows in-fighting within literaly the first week of gameplay. No one seems to be acknowleding this and just seems to say that Soryo type would solve all my issues when it obviously isnt. I've attempted both 10 and 11 start dates and the same issues of me being able to do literally nothing has appeared in both of them.