2003 volvo isx15 cm570 issues

[Magnat1976]

Hello to everyone
I like to ask your opinion or advise about my truck..
I have 2003 volvo vnl with 450 hp...isx5 cm570, 13 speed eaton for 6 years with 840k miles..now
I am experiencing weird issues especially when it's getting cooler, fall,winter times..
Feels that I am loosing power,especially under the acceleration on high gears 1100-1300 rpm..feels vibration,lack of power and when it's cold engine sounds like it's still cold..and it's 2or 3 winter like that.I replaced both coolant thermostats last season
Before truck ran perfectly, I hauled even up 100k pounds with no issues,and now even empty trailer I am pulling such a loaded.
Truck is at top shape,maintened ,no oil consumption, boost 23-25 at acceleration, no faults,no codes,everything OEM..overhead done,damper, engine brake rebuilted,
I greatly appreciate your advises,any ideas?
ECM can cause issues,because of age?without any codes?
Injector?cm570 never heard that they fail
Boost sensor replaced..
What else ?