when you land and need the gate ready without scrolling window to window, this is what I mean, not when u start a scenario
as u are saying...
There's no difference whatsoever between searching for a gate after landing and before starting a flight: the menu is exactly the same, and it surely doesn't take "20 minutes", but just some seconds, I'd say surely less than 20 seconds to find your gate.
And no, the SDK does NOT provide your assigned gate through Simconnect so, assuming you were asking if it could be possible to preselect automatically the gate that has been assigned by the ATC (and of course, it wouldn't be useful at all if you are flying online with a human controller), then no, it's not possible right now using the official SDK.