Shimano Alfine 11 – loosing my mind

Hi,

I have severe shifting problems with my Alsine 11 SG-700 from 2016.

What I have done so far:
Changes the shifter (on the old one the gear indicator was broken)
Changed the shifting cable and cable housing to Shimano optislick.
Fully disassembled the Hub, cleaned and oiled everything again.

The oil was very dirty with many small metal particles.
I was surprised by that because I changed the oil anualy which is around 2000 to 3000 km.

During disassembly I found some pretty significant wear of the plate that secures the planetary pins "Pos. 7 Y37R98020 Carrier 3 Unit".
Seems like "Pos. 10 Y3EN98020 Carrier 2 Unit was grinding on that plate.
See photos with arrows.
You can make out galling and wear tracks.

Gear teeth are in great shape, no visible wear marks.

One spring was out of place and inside a roller which is used in the clutch. Fixed that before reassembly.

Belt tension is adjusted properly, double checked with Gates Krikit (15kg) and Gates app (39-40hz)

No matter what I do with the cable tension, I can't get it to shift reliably.
Some times all seems okay until I coast for a bit.
If I then want to pedal again there it is spinning free, like in neutral.
Other times it's grinding away, cracking and not engaging gears properly or dropping out of gear.

Already starting to think I need a new hub which will cost me around 270€ SG-7001.

Any advice in what I might be missing?