Unable to see phone screen after connecting nebula capsule using cord

I have nebula capsule …and I have samsung s21 ultra phone…I know how to fo screen mirroring…I have issue when I connect my phone to projector using hdmi to usbc cord…it that time it shows like a laptop monitor on the wall where we are displaying projector content…I want to show my Netflix downloaded content. …especially when there is no range…so what can I do… please check