Basic screen mirroring should be available to an external TV or connected monitor with iPadOS 16.1. However, Stage Manager support for external monitors is not yet available - this feature being planned for release later this year.
Be patient. It’s coming 🙂
Screen Mirroring to an external TV or monitor preserves the iPad’s screen aspect ratio. Unless your monitor will scale the display to fill the screen top-to-bottom, you’ll see a border around the mirrored screen. If re-scaled, you will instead see black bars to the left and right.