I would like to know whether the new smart controller works with the mavic air? i was thinking about picking it up sometime, but not if it doesnt work with the mavic air.

Nope. Mavic2 only. Occusync 2 only.

M2 and apparently future drones with OS2

Nope, can't work with Mavic air. currently, it only supports the Mavic 2 Series.  Check the Specs.
https://www.dji.com/smart-controller/specs

Hi, thanks for the inquiry. Sorry that our remote controller is currently supporting drones that use Ocusync 2.0. You may refer to the link below for the for further details. Thank you for the support.

https://store.dji.com/product/dji-smart-controller

The controller would cost more than the actual drone.

HedsIc Posted at 1-8 09:58
The controller would cost more than the actual drone.

Yes

Has anyone found a replacement for the smart controller Power Adaptor QC24-US? Doesn’t seem like your normal 5 volt USB charger. If you read the manual it says it’s 12 VOLT 2 AMPS. The cable is beefier too. Neither are listed for sale on the DJI Store and I can’t find a generic version anywhere on the internet. A little worried if I lose or misplace mine that my Smart Controller can not be charged