I'm just not sure why you (or others) think there would be one more beta? The event is today (and quite likely the updated News app will go live immediately after), AirPods (2nd Gen) will be delivered starting tomorrow, and there is a possibility that the TV app will get something (though unlikely). I just don't see another beta. The only question is whether the final will be delivered today or tomorrow. Given the AirPods arrival on doorsteps tomorrow, possibly first thing in the morning, and the fact that 12.2 is necessary for the "Hey Siri" functionality to work, there's no way Apple is going to be in a situation where the Airpods lack key functionality for the first few hours of their use. Can you imagine the headlines?
12.2 will drop shortly after today's event concludes.