I will sedond the "learn the basics". Things that used to baffle me are now simple and easy to understand. I had a little knowledge and started writing an app. All of a sudden stuff came up that eiter I did not know, problems were cause by my misunderstand, parts of the code looked like magic to me and I would stick these totems, like @State, in my code without knowing what they did.
I went through the 100 days of SwiftUI course and a lot of things cleared up, I now what @State does, and I wrote code and "learned" things about the environment. You may think you know something but write a simple app to test and see if it does what you think it does and sometimes you find Oh, it doesn't work like that, it does this.
Just a little bit ago I was floundering, trying to use the tiny bit of what I knew to understand the huge world of Swift and the iPhone. Now, I am a little better.
One problem I had was I kept being tolt to write these simple useless apps. The app I wanted to write was useful. Write the simple ones and you learn the stuff that you can put together to write the useful app. You write the simple apps not to have an app that will pick from a list and not save that pick for the next time you run. You learned how to pick from a list. Another simple app saved some data, again not useful data. A third app showed you how to pop a sheet. Now you can pop a sheet, pick an entry from that list and save the selection for the next time the app runs, something your useful app might do.
I started out with an app in my head I wanted to write. I looked at an example that let me select from a list. Now I whated to pop a second view and save stuff to disk and a whole lot more. You can not start knowing nothing and write a complex app. You need to learn how to do simple stuff and put that stuff together to build your app. Alsong the way you learn how SwiftUI works and you can fit your vision to how it works. It's horrible if you go I want to do A and SwiftUI does not do A. Instead say I want 1 to happen and with what SwiftUI does, which you learned in the simple, "useless" apps, you simply do B, C, and D and then 1 is done.