FWIW I put a few hours into building a starting city, and no real issues with performance now in that a game like this clearly doesn't depend on smooth frames quite like a flight simulator does. I think there was at least one major patch since when I first tried it, which might have helped. There's lots of detail and modelling, this could be a bit of a dangerous time sink. :-)

I could certainly see why my old system (5800x3d / 3070 / 64) doesn't play it quite as nicely for my son's bigger 3440x1440x60hz monitor though; it certainly made the 4090 busy.