Fercik

Hello everyone,
I have an issue with om642 in w221 it has around 280000 km. The issues started after we left it sitting for 2 weeks.
We started it and it was making a terrible rattling noise. Xentry only showed "too many misfires" as an error. We knew injectors were not 100% so I removed and had them tested. 2 of them were bad so we replaced those and I installed them back.
Engine was running even worse and there was a lot of white smoke coming from the exhaust.
I tried to do further diagnosis and got to this:



I tried replacing the Y74 on the high pressure pump and also put in a fresh fuel filter. Somehow the situation got even worse. Now engine managed to only run for 2-3 seconds shaking violently and then stalls.
During the last diagnosis I also checked DPF and values were alright. (Slightly higher turbo pressures than the specified range were also observed during the diagnosis.)
Another thing worth mentioning that might be related is that I rebuilt the high pressure pump some 500 km before these issues started. I was replacing all the o-rings inside. But it was not my first time doing it and other cars where I did it work just fine.
I believe I took enough care trying to prevent contamination to the high pressure fuel system during pump rebuild and also injector change but it seems like to me that the high pressure system is plugged somewhere?
Or any other ideas? I am quite baffled and unsure what to do next.