Think this is a hard limitation of some sort on the M1 itself. This iMac seems like it's the Air version of the iMac, definitely not the "Pro" version. All the pro stuff will likely go there.
No dual out, though this is much better than a current M1 Pro as you can at least have a total of dual high-quality desktop displays. If you want more you can get a DisplayLink as a stopgap for now.