Fuel low pressure sensor pinned at 89psi

[n54boost]

2009 535i - Been having this fuel issue where my fuel pressure psi will get pinned to a set number my specific issue it gets pinned around 89-90psi, when the car starts like this within a few minutes of driving or idle it will go into limp mode. this is not all the time, I can get my car to start and run well with no pinned number, after several times restarting the car. Also, I am not getting any codes. Any who...

Everything I have tried so far:

-New low-pressure sensor
-complete low-pressure fuel system (just upgraded to Fuelit stage 2 pump. New buckets line everything)
-New EKPM3 (I did code it)
-New High-pressure fuel pump, but an Amazon special so I'm thinking the problem is it's from this sh*tty Amazon pump and I just need fork the $1100 for one off FCP

please Lmk what yall think