I am looking for a wifi adapter that supports all of the following:
-2.4 + 5 GHz,
-AP/master mode,
-monitor mode and packet injection.


Is there actually such a thing?

I am only aware of the Alfa AWUS036NHA, but this does only 2.4GHz.


What about the following products? Do they support all these things, specifically, did you test it in AP mode (master mode)?

Ralink RT5572 / Panda Pau09
Realtek RTL8812AU / Alfa AWUS036ACH
Realtek RTL8814U / Alfa AC1900