If you follow the internet and especially some well known Youtube channels then Nikon are doomed and failing and about to go bust.
Actually Nikon are doing well. Stock is low and it can be hard to get stuff but with the world semiconductor shortage everyone is suffering. Canon have just admitted that the new R3 will be in very short supply and it looks like the Nikon Z9 may be delayed. The Z cameras are competitive, each new firmware upgrade has improved them. I feel where they get a kicking is generally either because something works differently then other manufacturers or like the banding issue with the original Z7 (what issue who underexposes by 6-7 stops) is also a problem with other manufactures but no one is talking about it.
I like two card slots but its a very niche case for people who actually need them. Yes its useful for backup if your using SD cards which can suffer from reliability problems but the new CFExpress cards are engineered not to suffer from the software and hardware issues that SD cards suffer from. Nikon did listen and put two cards in the mark II models but I would have preferred two CFEx card slots and not CFEx and SD.
So where are Nikon a head, or behind, well I feel Thom Hogan in a recent article wrote about this best so go and have a look on his zsystem web site.