Thanks, shall36, that what I thought as well. I think, condenser may be a suspect too, but I don't see how to prove/ disprove this. The high side charging inlet valve is located BEFORE the condenser and the low side one is AFTER the expansion valve.... Surprisingly, the AC is ice cold once compressor engages.... Ah! Here is an idea: I replace the pressure sensor (located between condenser and expansion valve) first and will compare its value vs the pressures at high side charging inlet. At this point, there is a difference in about 5 bar between them, but I can't trust the pressure sensor at the moment. If I replace it and there is still a big difference in values - then it can be a condenser as well.
If I am going to replace a condenser, I'll anyway replace the dryer and the expansion valve. But if the issue is not in condenser, I'd better replace just the dryer and the expansion valve only.