You can certainly use the Classic workflow. The Z30 should work. You can ignore the warning to use the DJI Workflow if you want. It is just better to use the DJI one when you can.
Email one of your images to us at mapping@dronesmadeeasy.com so we can see what is going on with the tags in the Z30 images.
The Z30 is not a great camera for mapping but it should still work. It might be an issue with the adjustable focal length.