There are only two staves on the Piano II staves and I want to remove both of them after 2 beats. I tried to use the “Remove Staff” option but Dorico stopped me from doing this. The screenshot should make it clear (Piano II, Percussion I and II have the same problem too)
It looks like you want to work with a cutaway score. If you search the forum you’ll find several topics/threads on this that have been added to within the past couple of months.
Here … with some reservations, because it is not really consistent and more a way of trying out different things. I guess I would not really recommend this, until Dorico gets native support. But the discussion mentioned above in this thread has good info.