I need help no big spoilers please

[Business and tie]

What’s the second route for psycing in the main. I already choose the route where you believe iris, and I got the iris ending. I have the mizuki and ota endings too. But a route where boss kills So is locked. How do I trigger the second choice for psycing in the main. When I talk to iris I only get one option. And there’s nothing else I can do, right? What am I supposed to do?

[Tale]

https://steamcommunity.com/app/948740/discussions/0/1628538005514253688/

[Business and tie]

Thank you