Looking for some advice: we are planning to create a hybrid app for both iOS and Android; this app will consume a REST API. We are looking for a tool for this development with the following attributes:
Shallow learning curve; easiness to adopt (all team is new into mobile development, with diverse backgrounds: Java, Python & AngularJS),
Easiness to test (we discarded Angular-based tools already: creating a unit test in Angular we considered time-consuming and low value. At this point of the project, we cannot afford UI testing with Selenium/Appium based tools).
So far, we are not considering any specific capability of the device. Still, in the mid/long term, we would require the usage of GPS (geolocalization) and accelerometer (not sure if it's possible to use it from a hybrid app). Suggest any other tool if you wish.
If you already know how to build web apps, give Capacitor a try. You can think of it like "electron for mobile" in that you can build a web app but access native functionality. Pair it with Ionic if you want a UI kit that is optimized for mobile, or build your own UI from scratch.
A bonus to Capacitor is your app will run without modification on the web as a PWA, iOS, Android, and more.
If your team has a strong background in Python and you want to release some prototype soon, you could try Python and Kivy. Kivy is an open-source, cross-platform Python framework for rapid development of mobile GUIs. It supports both iOS and Android. I have passed a similar situation recently: to start a mobile app with no background in mobile development. Kivy saved me a lot of time. I could develop a prototype and release it faster than I thoght.