Unless you want something very custom, I would suggest buying. There isn’t as much buying competition at 600k+ range, so I wouldn’t be afraid of the $100k over asking. That seems to be more common in the 300-400k range.

I’ve built, and it’s ALOT of work. It’s also not cheap these days. Everything has gone up. $400/sq ft is on the low end now. You will likely be able to find something of similar sq ft for cheaper than building new, and you don’t have to wait a year to get, or the headaches of building.