rotate macbook

Are you talking about the built-in screen of your MacBook Air, or an external display?

External displays can be rotated, the built-in screen cannot, as far as I can tell.

If you did rotate the built-in display, I would really like to know how.

There is no option in System Preferences to do it.

If you mean an external, open System Preferences->Displays, click Display Settings and make changes in the Rotation pop-up menu:

Note how there is no corresponding pop-up for the internal display:

I am sorry but that capability appears to have been removed in some iteration of macOS. Older macs, perhaps at High Sierra, could do that. That is no longer possible in Monterey. I am not sure exactly when this was removed, perhaps in Big Sur, or Catalina.

All any of us can do is let Apple know.

https://www.apple.com/feedback