Nothing wrong here at all.
The perception of high Fe and Cu is because of two things:
1) Most BITOGers simply are afraid to run that far, so they don't see totals that large
2) Fe accums with miles- we know that; Cu is a trend in many GM vehicles due to the oil cooler circuit which has Cu tubing. Nuff said
On a PPM/1k mile basis, this is a great run. Very low Si; air filter is fine and you should leave it alone! Don't even think about touching it. Other stuff like oxidation and nitration are OK. No coolant intrusion.
TBN/TAN are basically a moot issue when you use the vehicle frequently and get it up to temp. That keeps the moisture out and therefore acids don't typically build to any large level. We've seen many examples of the infamous feared "cross-over" and nothing ever bad happened. This was a big issue way back in the day when engines were not sealed up well, and both the fuel and oils had lots of sulfur; not the case anymore.
Nothing wrong with a 20k mile OCI here, despite the fear that some have. Use a good quality filter and keep on motoring. That little 4.8L is doing fine.