My understanding is that many of them can be wired as 1, 2 or 3 phase at least in Nordic countries, though admittedly the ones which allow 3 are somewhat rarer especially when looking at stove top-only models (not combined stove+oven).

Good we have one. What a nice 0% we are.

I'm pretty sure most of them just use a higher amp circuit. A 40 amp circuit at 230v is 9kW which is more than enough. I've also seen one particularly high end stove which used a battery to cover the extra power needed for the highest setting. Also means you could use it in a power outage.

My common model IKEA stove – rebranded Siemens or Electrolux – runs at ~400v (Northern Europe). I know because it broke and I almost poked at it, until I got spooked by the warning labels. It's on its own circuit. Not an expert but as far as I know, most houses in Western/Northern Europe have a three-prong stove/oven connection in the kitchen for a ~400v feed.

I have a three-phase 'smeg'.

We have that particular model because it was literally the only induction cooktop on the market that would fit the existing hole in our stone worktop.

Quite a lot of them can be wired either one, two or three-phase when you look into their installation instructions, it's just that not that many houses have three-phase power and not many people are willing to pay to get that upgraded just for the hob.