P0170 Fuel Trim Issue in 2005 Mercedes C230 Kompressor - Fix After MAF and Vacuum Line Replacement

I own a 2005 Mercedes-Benz C230 Sport with the 1.8L Kompressor engine. I've been experiencing persistent P0170 and P0171 fuel trim errors, where long-term fuel trim (LTFT) was previously over 25% before. After replacing the four vacuum hoses behind the supercharger that were damaged, I also installed a new MAF sensor from Germany and replaced the pre-cat O2 sensor. Despite these repairs, the only remaining code is P0170. Using a torque app as my scanner, my fuel ratio fluctuates between 12.9:1 and 14:1, with stoichiometric oxygen sensor readings dropping below 1.00 under load. Currently, LTFT has stabilized at around 10.2%, while short-term fuel trim (STFT) at idle sits near 0±1–2% until the engine is under load. When the P0170 code reappears after clearing the memory, the freeze frame shows STFT at or near zero—yet the code persists. I've read that a fuel adaptation reset should be performed after repairs like these. Is this correct? Or could there be a deeper issue causing my fuel ratio to remain high and O2 sensor readings to drop below 1.00 in closed loop? In closed-loop mode, I observe a fixed 1.50 O2 reading and a stable 14:1 air-fuel ratio, but as soon as the engine transitions into closed loop, the values begin to drop. Could this indicate a faulty oxygen sensor or another underlying problem?