Judging from forums etc, the key to empower DX and widen affordability of the Z system for action genres is a Z90: with AF at least matching that of the excellent D500. Such a camera should cost relatively less (than a Z9): if the smaller sensor cuts the net cost of a MILC with stacked sensor. Judging from the D500, a Z90 will be used with FX glass mostly.
A 10-20 DX in Z mount will close the biggest gap in the line up. The compact 16-50 DX Z will also be ideal as semi-fixed lens/body cap - types 45 f2.8AIP
Whether it is DX or FX, as we know almost any lens is adaptable to its Z-mount. Indeed, many see a big anticipated role of a ZFc to inject new life into classic glass (mostly FX lenses as said above). Nevertheless, 3 years into the Z system - since release of the FTZ - Nikon still ignores the lack of automatic indexing of the aperture ring on AI / AIS lenses. Equally, owners of older Nikkors still cannot get full AF with a 28-105 AFD, 85 f1.4AFD and all the other screwdriver Nikkors on Zed cameras.... This includes the Defocus-Control primes.