Take your pick. There’s no special magic to Japanese cities. They’re dominated by traffic and construction, full stop. The air is filthy.

Well not all Japanese cities are the same, and it is unfair to categorize a megalopolis like Tokyo as one thing or another as it's too varied for that.

While Tokyo does have no shortage of highways and cars they do have plenty of mixed zone medium density, walkable areas that are free from car noise. That is not a feature of any part of most US cities except maybe the CBD. It is also much more uncommon to find stroads in Japanese cities, while a stroad is the default for many western cities.

Sure, smaller cities are better than big cities. Less dense cities are better than denser cities. All else held equal.

The neighbourhoods you’re referring to - walkable areas free from car noise - are open to the wealthy only. The absolute vast majority of people in Tokyo live with constant traffic noise and terrible air quality. Not to mention cramped living conditions.

It is really, really hard to compare metro areas without actually having lived there.

Tourist areas are always by definition in nicer parts of the city because the tourists pay for it.

And if you have enough money most cities have nice parts. But how does the “average” working stiff live?

It definitely is difficult, thank you. It also seems to me to be of limited value unless you’re specifically trying to measure the effect of different policies. Let’s just do what we can to improve air quality everywhere. We know diesel bans work, we know EVs work, we know congestion pricing works. Let’s just do it - especially for our kids. Doesn’t seem particularly controversial to me.