The Air is better than the original Pro in most ways except:
1) Maximum range (4km vs 7km), but in most countries you need a dedicated spotter to be legal if you fly beyond visible line of sight, so maximum range is very rarely the limiting factor. Make sure you are familiar with the laws of your area.
2) Battery life - you get about 7-8 minutes more flight time out of the original Pro before it's time to come home based on best practices (RTH around 30%). Certainly this is useful if you need more than about 17 minutes flight time.
3) The Pro is a bit quieter, but they are both loud enough to attract the same attention. Neither is at all quiet. The Air has a higher pitched sound to it.
The Air is approximately 2X smaller and 2X lighter, has much better obstacle avoidance, significantly better video quality, and has a much better gimbal design. It's a newer drone and it shows. The remote is a better design as far as portability is concerned the removable joysticks, but you give up the LCD screen (the same info is shown in the app). It will also fare better in a crash with the protected gimbal. They both are rated for the same wind resistance. The Air also has 8GB internal storage if you ever forget your memory card - this is potentially a life saver.
If neither size nor cost is an issue for you, the
Mavic 2 improves on every shortfall of the original Mavic, but especially as a beginner I think the Mavic Air is perfect and it is capable of very professional results still. I don't think you need to be feeling any buyer's remorse - the Mavic Pro is almost 3 years old now.
Personally I went with the Air for the better image quality, huge size/portability advantage (I travel and hike a lot), newer technology, and I will never need to fly beyond 4KM. I fly around urban areas all the time and have never had any issues with signal strength. YMMV.