I don't doubt some are having real change and others don't, and here's why.
Even with the original 2019 GTI tune, some had issues, some didn't, even with the same tune.
The reality is, between slight manufacturing variations from car to car, different driving conditions, different fuel,, different driving styles, some cars DIDN'T have issues to begin with. My car would be fine when all adaptions were initially reset, then get progressively worse, until I started having stalling and the car felt like it was running stupid rich below 4000rpms, then would clear up. O2 sensor ended up failing, they replaced it, reset adaptions and put 5w-40 in my car and I didn't have anymore issues. Some never had issues with stock tune and 0w-20. Some tried heavier oil and still had issues.
I live in a real hot climate AND the times the car got really bad were ALWAYS after an autocross or a track day. I just don't think the stock tuning of the vvt took really hot oil 0w-20 and hard driving into account, and the ECU was getting erroneous timing data. The car then "learned" based on erroneous data.
If you lived in a cooler climate and didn't drive it as hard, you might not of had any issues ever with the 2019 tune, even before the first fix.