No, both 1x and 2x drivetrain setups use the same Rival AXS rear derailleur that works with cassettes from 10-28T to 10-36T maximum. The Rival rear derailleur is spring clutch equipped for excellent chain management in both 2x and 1x applications.
Using a 10-50T, 10-52T, or 11-50T Eagle cassette in a 1x configuration will require an Eagle AXS rear derailleur an Eagle chain. Eagle AXS rear derailleurs are not compatible with a 2x system.
Learn more about available gearing options in our article, The Right Rival Gearing For You.