4.2L O2 Sensor Codes. Easy fix?

[Squenz]

Hey guys. I'm new to working on Audi. My last project car was a '66 Mustang so a lot is new for my, like oxygen sensors. I'm routinely getting these codes.
What kind of expense am I looking at?
I imagine these parts are easy to replace, but if it's a vacuum leak issue that I have to track down, I'm not as confident.
What's your diagnosis, doctors?

2010 S5 Manual 4.2L V8

P2006 Intake Manifold Runner Control Stuck Closed Bank 1
P2007 Intake Manifold Runner Control Stuck Closed Bank 2
P2198 O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 1

Thanks!