There are several possible causes and you appear to have addressed some of them. First question is to do with the parts you used in the repairs/maintenance. When you say you replaced parts did you you all new parts including the turbo? Is the turbo from a known good supplier? When you replaced the v...

Annoying as another post I made has disappeared! In that I mentioned a suggestion to do a glove test as suggested by Sveedy above. Put a rubber or latex glove over the oil filler with cap removed. Start the engine and see if the glove rises, does nothing or get sucked inward. If either of the first ...