BMW X3 E83 2.0d 150 HP, 340,000km takes a liter of oil per 1000k

Hello interested
I do not know if I have posted in a good section, so please be patient. I have a BMW X3 E83 2.0D 150HP, mileage 340,000 km on the meter, 2006 The car takes about 1 liter of 5W30 oil per 1000km. I bet on rings and valve seals because in -20 degrees Celsius there was a problem with ignition. The turbine was regenerated some 15,000 km ago, the engine was quite dry, the pneumothorax changed, etc. I measured the pressure on the cylinders myself - a large discrepancy in measurements, I do not remember exactly but somehow; 1- 22 bar, 2- 23 bar, 3 and 4 27 bar. I am looking for a good mechanic from around Warsaw who will do renovation in reasonable money. I wanted to sell the car and exhibited on the announcement portals, but who saw this course and the description that it takes oil is not interested (I am not surprised) and whoever is interested wanted to break the price specifically despite the fact that it was already underrated for renovation in / in faults. The car is in good visual and technical condition and that's why I decided to fix the faults and keep it to myself. Maybe it would be better to replace the whole engine than to renovate this one. By the way, I want to replace the double mass because it rattles when disengaging and delete any slack in the suspension. I wonder how much less oil it will take if from 5W30 I switch to 10W30 (some semi-synthetic)
If anyone can recommend a good and honest mecha to me, I don't have to be from Warsaw alone, I would be very grateful. Alternatively, I will listen to wise ideas on what to do with this car
Once on some BMW forum I found boys from Gliwice or Katowice who were doing engine repairs and filming it on YT, from these materials it seemed that they were overwhelmed.

Use 10W40 oil instead of 10W30. Higher lubricity. However, this will not solve the problem. Maybe it'll reduce the leakage a little. In my time I was doing a major refurbishment on the VW 1.9D. I regret it today. Engine on good parts, renowned workshop, equivalent to 3 used engines in good condition. 80,000 each he took approx. 0.7L / 1000km and then I could not keep up. He didn't kick, he smoked to touch in all conditions. Diagnosis without demolition: valve stem seals.

I do not know how much to give for a Bm.ki drug but I would look for it.

You can replace the rings themselves, but only after dismantling you will find out whether it makes sense.

Better post from the Englishman

Pull off the intercooler hose and see if there is sometimes oil. In this run, turbo can pour then regeneration, dismantling the bowl and cleaning the dragon after the problem .

Turbine regenerated some 15k ago, nothing helped in taking oil. Poor pressure on the pots (as I wrote above). I think, however, rings and possibly valve seals.