Using Unity 2019.3.14 or later - including Unity 2019 LTS - Vuforia Engine fails to initialize on iOS devices. This also affects earlier versions of Vuforia Engine on those Unity versions. We are working with Unity to resolve this issue as quickly as possible. In the meantime, please use Unity 2019.3.13 or earlier.
Vuforia Engine Support
Fixed with 9.2.8