Yes, Z4 got android 10 shortly after launch

The Verizon Z2 Force (for the 5G Moto Mod) and International variants got Android 9. You can flash a hybrid official Android 9 firmware (done by flashing specific parts of the newest available Android 8 firmware and parts of the Android 9 update in a specific order to get it to work. I flashed both my Sprint Moto Z2 Force phones to Android 9 as soon as the instructions came out how to do it on the XDA Developers forums like a year or so ago.

You can flash XT1789-05 stock to an XT1789-04 to get Android 9 Pie. From what I can tell there are no negative side effects, might have to manually configure APN