I'm just speculating, but based on the lawsuit between Broadcom and Apple, my guess is that Apple will adapt Intel's CNVi Wi-Fi sooner rather than later. Plus, it's probably less expensive for Apple too.
That being said, for the time being, until Intel Wi-Fi support has been confirmed, M.2 (E Key) slots on Z390 motherboards that are compatible with non-CNVi will still be important. I don't know if the Asus motherboard you had made special provisions for compatibility or if all Z390 motherboards are compatible with standard M.2 (E key) cards. On H370 and B360 motherboards, some people tried unsuccessfully to use standard M.2 Wi-Fi/Bluetooth cards in CNVi M.2 slots. I believe they had Gigabyte motherboards.
I think that your success in getting USB to work bodes well for all Z390 motherboards. I would not be concerned about that.
Your sleep/shutdown issues may require Clover updates to fix. I remember when Z170 was new and sleep was quite spotty for me at first. Eventually, one of the Clover releases fixed it.