Pinging noise and hot engine 1.4 BBZ

[Crt_cc]

Hello everyone, I need help on a VW Polo 9N3 1.4 BBZ.
The engine suffers from severe spark knock/pinging under load (around 2000 RPM) and runs excessively hot.

Here is the live data from OBD (Car Scanner):
• Long Term Fuel Trim: -23.4% at idle.
• Short Term Fuel Trim: -6% at idle.
• Engine Coolant Temp: 95°C cruising at 60 km/h, climbing up to 104°C in city traffic.
• MAP Sensor: Reads normal, 36 kPa at idle.

The radiator fan 1st stage seems not work, it only kicks in at 103°C. I have already replaced λ sensor, radiator, water pump, and thermostat twice. The throttle body has been cleaned.
What could be forcing to pull 23.4% of fuel, lean condition and knocking under load? Could a wrong fuel filter or a faulty EVAP/EGR valve? Any insights on what is the problem would be highly appreciated!