As an earlier post of mine is being quoted in part without attribution, I’ll fill-in the rest of the explanation…
Dynamic volume controls were introduced with release of iPadOS 15.4 onwards. For reasons known only to Apple, the ability to either enable or disable this feature was not available for the iPad Air5 and iPad mini6:
Use the Home, side, and other buttons on your iPad - Apple Support
New models of iPad launched to market after release of iPadOS 15.4 (initially iPads Air5, mini6) had this feature “baked-in” to the User Interface (UI) - with no ability to disable the dynamic controls. The 2022 11” and 12.9” iPads Pro and the iPad10 are the first new models of iPad to launch since introduction of this feature. It is therefore feasible to presume that dynamic controls are similarly a standard element of the physical UI of these new models.
Apple have not updated their documentation to indicate that the 2022 iPads Pro and/or iPad10 are similar in implementation within the iPad Air5 and mini6. Hopefully Apple’s documentation will provide needed clarity in due course.