This one could be tricky as not even the Ross Tech wiki has P3089 in it.
Not wanting to teach you to suck eggs, but if we go back to basics..... the engine ECU commands a certain pressure (between 3-6 bar) from the LPFP, depending on load/rpm. It determines that from the low pressure fuel sensor, which is bolted into side of the HPFP.
The sensor on top of the HPFP (the one that always snaps) is the 'thrust sensor' and that manages the high pressure side for the DI injectors, based on feedback from the high pressure fuel sensor, which is the one in the fuel rail.
The ECU communicates with the LPFP controller over CAN, and the HPFP is controlled directly from the engine ECU via High side sensor and thrust sensor.
On top of all that, the LPFP also has a relay and a PWM module. It's all a complete minefield to diagnose.
Most, if not all of the engine sensors share a common 5V reference line. I can see your intake runner flap has a short to ground, so it could be related. A lot of the time with things like this, you fix one thing and it fixes everything else. A lot of the fault codes can be red herrings chasing you down the wrong path.
Diagnosing CAN signals can be fun, not. A scanner with a scope function is normally required, but I can't remember if VCDS has that or not.
There are still some clues there the CAN gateway could be unhappy, or there's a bad wire/connection somewhere in the CAN network as there are some other modules that are unhappy too, like the ABS/Steering, lights, HVAC, door controllers etc.
I hate to say it, but I think it's going to need a lot of end to end continuity testing with a meter
I'm not sure forum assistance will be much help. I think this needs an auto electrician to systematically go through it all as they have access to equipment we don't.
Good luck with it. You certainly deserve a break as it's been, what, 8 months or so now?
