35d Limp Mode, Several EGR Related Codes

[M62 X5]

Picked up a 167k mi 2012 E70 35d a few weeks ago and the problems started almost immediately (I expected this).
After a week of driving, I got a CEL and scanned it with my generic scanner to get the P20EE code for NoX sensors. Since I only had my generic scanner on me at the time I decided to clear the code and see if it came back. It returned about a week later but this time I opted to leave it be and drive it to work to see if I could scan it with a better scanner and get a better idea of what code it is. Unfortunately when I went to drive it to work it went into limp mode merging onto the highway. To get the car out of limp mode I had to clear the code and drive the rest of the way into work. I figured it would be another week before it came back but upon trying to leave work the CEL came on and it immediately went into limp mode this time. I pull codes with a Foxwell scanner and got the following codes:

40D4 DDE: Exhaust gas recirculation controller position control
44DA Exhaust gas recirculation-rate control, control deviation
4862 DDE: Air system, air to EGR mass flow, plausibility
48DD Charging pressure sensor, plausibility
4B81 DDE: Exhaust-gas recirculation-rate control, control deviation
4C8C Exhaust backpressure before turbocharger, plausibility

I did some searching and found other threads where some similar codes were fixed by a MAP sensor replacement. So I removed the MAP sensor to check it and it looked fine, just a little oily. I wiped it off and then replaced it. Drove it around the block and no limp mode. I did also watch the boost pressure during the drive and it looked normal.

Does anyone have any insight on these codes? I'm a little stumped why initially I had NoX sensor codes but then after the limp mode incidents I had EGR and air metering-related codes.

TIA