Hey guys need some help and ideas

i have an issue with my truck not making fuel pressure it gets to around 18,000rail on wide open throttle
i would expect that when I floor it that the frp should just straight to around 26,000 ish
mine seems to slowly creep up and only after holding wot for a while will it make it to 18,000

the truck has edge tuner
60hp injectors
bd diesels 150lph lift pump

The truck starts and runs great idles no worries and seems to do everything smoothly just lacking some power.

i have changed fuel filter it was clean
checked voltage to lift pump 14.4volts
changed fpr relief valve and for testing it has a plug in it for now

no fuel in the oil and starts and runs clean so guessing injectors are ok
they are reasonably new

not sure what to check or look at next

is there any in line filters or any gauze filters in the banjos or anything?

any help appreciated

thanks in advance!!!