Tiny RTK Module

if the Tiny RTK module is used with the ublox, it means it does not need a GPS since the ublox chip is already a GNSS?
Additionally, which one could be the rover if the XXL RTK base is selected? not so clear to me.
the best option along with the pixhawk 3 pro is the sirius model? if so, any base module can be used?

Thanks

The perfect combo for the Pixhawk 3 is this kit https://drotek.com/shop/fr/rtk/866-gps-rtk-kit-sirius-neo-m8p-2.html?search_query=rtk&results=10