You can convert a PWA to native/hybrid App and vice versa, but you must understand the limit of each model. PWA requires service workers to run on browser and provide offline access and/or web notif. On the other hand, hybrid app use Ionic/Cordova to provide same services. so the implementation must be different, but the gap between one mode and other depends on native resources your App requires.
I recommend you to read Using Ionic/Cordova app sources as PWA to understand how to switch form a pwa Ionic implementation to native app, and vice versa.