2013 ISX Loosing power when engine is warm

[TXRS]

Hi. l have freightliner Cascadia with ISX 2013. 950mileas Truck is deleted. (for sure not good tune)
Truck in past 3 years had replaced turbo 3 times. Last one l replaced due to sized turbo ''flap'' arm(was throwing codes for actuator calibration)
Overhaul was done 1 year ago (no issues with that) just info.
New all 6 fuel injectors, new head, liners protrusion 0.14
Fuel pump brand new all assembly 1.5 year old. checked already plungers and pump is fine
2 or 3 EGR coolers replaced in past 3 years(not sure what reason i think it was antifreeze leak) EGR valve is unplugged.
Exhaust pressure sensor new and clean tube
Boost pressure sensor 5months ago
Barometric press, sensor is new
Tune up done
No boost leaks

What l can see truck is loosing power, with pressed accelerator pedal on hill (bobtail) truck is not accelerate as should. speed stays same or even dropping down little. At this moment fuel pressure commended and measured is same 32k, exhaust pressures is 100-120inhg, boost pressure max i saw 50inhg. turbo actuator position is same as commended. The driver said it is hard to pass from 1400 to -1650rpm then truck gets power back(it is like boost lag at this rpms) just with load it takes from 58mph to 70mph very long time even on flat road.
This happening when truck is warmed on cold not at all, also is not happening all the time but most of the time on hot engine. Driver mention that in states where it is very warm it is worst(even more power he loosing)
Done test drive with open exhaust pipe(same)

There are codes for inlet NOX sensor(truck is deleted but wires were damaged, i have fixed them but code still appears, sensor is plugged in.)
SPN355 FMI N/A, 2 COUNTS when he come to the shop now is not returning back couple test drives.
SPN 171 fmi2 not active but comes back each time. l think just a sensor.
Truck now is in Illinois

Any good clues? i know it can be many things but still l need someone who may had similar issue or just ideas