I have an iPad 2018 (same A10 CPU as the iPad 2019) and Zwift runs fine with it. You get no shadows on the riders but otherwise it runs fine. No ANT+ support though.
You can run Zwift interchangeably on any device. I use Zwift on my iPad when riding; and on my Android phone when running on the treadmill. You can also run the Companion App interchangeably, even on the iPad, although it only works in phone mode.