The spiral function must be something that is supported in DJI’s MSDK v5. As a result, it can only be supported in a drone using the Litchi Pilot app. Your DJI Mini is supported in DJI’s MSDK v4 with the regular Litchi app.
While a spiral can be created with a POI and a number of waypoints, that is not how this function is implemented in Litchi. If you want to create a spiral in a Litchi mission for the DJI Mini, you could use my “Spiral Mission Creator” software.