Does my turbo need replacing?

2016 Pete 389 ISX15 2350
1850TQ 550HP
Emissions intact and working good.
Forced Regen showed low soot load

I bought this truck a few weeks ago and right away I noticed under a loaded trailer that there is a real lack of power in the top gears.

Engine runs great. Doesn't use oil, no noticeable blowby, coolant stays level, starts good, idles smooth. Turbo gets up to about 38psi wide open.
Everything seems perfect except when I hit a hill or even when Im on fairly flat highway and try to get to highway speed (62mph)...it falls on its face in 16th to 18th gears.

HOWEVER...about a week after I bought it...I noticed that the wrong air filters had been installed and air had been getting past them.
I got a sick feeling in my stomach and pulled the filters. There was a little dust in the intake tubes. Took a look at the turbo and there was a couple very small nicks and not as sharp edged as new. But it still produces 38 pounds at full throttle.

So, I'm wondering if the turbo could be the cause of the low power at top end? Or maybe I'm just not used to driving trucks with emissions still intact and it's normal to fight the hills...but I doubt it.
- Did a fuel leak down test and it held really well after engine shut down. Lost about 1000psi in a minute.
- Did a cylinder cut out test and each cylinder made noticeable difference when shut off. When turned back on it sounded great again.
- Cleaned the MAP sensor and the differential pressure sensor. Both are still red and I'm assuming original...but weren't super crusted up with soot.
-Exhaust back pressure sensor looks like it has been changed because it's shiny and not red.
I'm attaching a picture of my turbo fins for reference. No play in the turbo side to side. No play in/out.
Any ideas or help is greatly appreciated.

 

That was my next guess. Problem is they are a pricey part. Be nice to know for certain if that's what it is.

 

Do you think that could be the cause of low power? It seems to be making full boost and holding it.
I'm getting no codes for anything so I'm kinda at a loss of where to look.
Started on cheap stuff with fuel and air filters. Cleaned some sensors (might still change IMAP sensor because it looks original and it's not too expensive.
Turbo and fuel pump were my next guesses.
I am considering removing emissions. That would rule out the DPF being clogged at least.