I expect it will be a long, long time before Zwift releases a BlackBerry native app. However, I have side loaded the Android app to my Z30 (OS 10.3.1.1767) and it is working very well. A little slow to boot up like all Android apps on a BlackBerry, but from them on it seems to be working perfectly.
I wasn’t able to find the app on Amazon appstore, but it is available from Mobile 1 Market. (If you don’t have the Mobile 1 Market app, search crackberry.com for instructions on how to load it onto your phone.)