With release of iPadOS 16.2, Stage Manager support for external monitors display support is available for these models of iPad:
- iPad Air (5th generation)
- iPad Pro 11-inch (all generations)
- iPad Pro 12.9-inch (3rd generation and later)
More information here:
https://www.imore.com/how-use-stage-manager-ipad
Move, resize, and organize windows with Stage Manager on iPad - Apple Support
Feature availability is usually limited by system hardware - CPU and available RAM being critical to some advanced functionality. Models supporting Stage Manager have an M2, M1 or A12X CPU (upon which the M-series CPUs are reportedly based) - with at least 8GB RAM.
The iPad Air5 specifications lists the following information for supported video output:
Digital video output
- Native DisplayPort output over USB‑C
- VGA, HDMI and DVI output supported using adapters (sold separately)
As such, you can directly connect the Air5 to an external monitor that itself supports DisplayPort over a USB-C connection (i.e., DP Alternate Mode over USB-C) - or using an appropriate adapter can also connect to monitors that have an HDMI, DVI or VGA (analogue) video connection.
Full specifications for the iPad Air5 can be found here:
iPad Air - Technical Specifications - Apple