Hello everyone, I'm hoping to find some assistance here, I'm really stucked and don't know what to do next, even the official service center didn't help me.The car in question is an A180, 2013 petrol model.

I have the following errors:
P052E71 The valve for crankcase ventilation has a malfunction. The actuator is blocked
P014013 The signal of oxygen sensor 2 (cylinder bank 1) does not change. There is an open circuit.
P013812 Oxygen sensor 2 (cylinder bank 1) has a short circuit to positive. There is a short circuit to positive.
P014100 The heater for oxygen sensor 2 (cylinder bank 1) has an electrical fault.

I've been to the official service center, this is what has been done till now:

So, I've replaced the O2 downstream sensor, after catalytic (OEM sensor), but nothing changed.
There was some harness issue with the cables and some pins, but the service confirmed that everything is now in orderm they have replaced pins and incorrect cable.
They propose now to replace ECU, even if they can't guarantee that it will resolve the problem.

I understand it's an older car, and they might not want to spend much time on it anymore, but I don’t feel confident they truly understand the issue.. I've been to the service center several times, and each time they say the car is fine, but the engine light comes back on after driving a few kilometers (once the engine reaches around 90°C).

Can you advice what to do next? Should I replace the o2 upstream too?