I recently finished building an mac/ios app following the tutorial called iOS App Dev Tutorial. I am really impressed with the tutorial. I was able to follow the tutorial (with some googling for missing content) and successfully built an app for scrum meeting.
Shout out to the tutorial for emphasizing to build with accessibility feature.
Since my development journey has been from backend to frontend to infrastructure, these are all web technologies. I have not really built an application intended for an operating system. (Actually, I built an Windows application with Visual Basic at school)
What I learned from building an app is that though there are vast different between app and web, the basic concept are pretty similar. An app and a web app organize their code with model view controller, using a store (like Vuex) as a source of truth for data, and using parent and child model to control user flow.
Now that I have some idea how to build an app, I hope that if the web development is gone, I have something else to fall back to. :)