We own a 2016 S and 2020 3 and I will say panel gaps are real. Coming from a Porsche 911 and BMW, I can see why some people are so anal about it. It drove me nuts at first.
But that’s not to say new bmw and Porsche are always perfect out of the factory. I have had my fair share of issues with them also. The quality is acceptable and will improve over time. For most people, you won’t even notice it.