ALOT, generally speaking, DJI's best in class drones will be labled "pro" and the mid class is named "advanced".
The P4 Advanced is basically the original P4 with a slightly better camera.
The P4Pro has 360 degree obstical avoidance, 1 inch CMOS camera sensor with 20MP, and a mechanical shutter, dedicated uplink and downlink wifi connection that uses BOTH 2.4 and 5mhz, and is better motors.
The P4 Advanced makes no sense other than DJI's attempt to make more money on old P4 bodies. They discontinued the P4 (which sold for $849-999), added a slightly better camera to it, shipped a new name on it, and raised the price by 400-500 dollars. Its crazy!
Additionally, the P4Pro is on sale right now for $1399, only $50 more -- which makes the P4 Advanced even more ridiculously overpriced.