Differences between Netgear Orbi models?

Fairly recently, Netgear released their WIFI 5 Orbi product.   I kept an eye on it for a while and recently checked back to the site and blam, there are a few versions of this product offering -- but nothing that really describes what (if any) meaningful differences there are.  For example, the AX6000 must be purchased elsewhere -- is that because it's replaced by other models?   The number incrementing in product IDs doesn't really tell me anything.

So, does anyone know the real differences between these WIFI 6 Orbi products?

Thanks.