Give yourself write (and read) permission to the stated build dir using sudo chmod +rw {dir} also ensure you are the owner sudo chown {user}:{user group} {dir}.
Now execute the first of your stated commands : without sudo. It should work. The message started you did not have write permissions, so make sure you do by changing ownership and permissions.
You can check both using ls -la {dir}
Proper typing of nested or generic types. For instance: generic classes or array elements without phpdoc's template.
For me the typing of array elements is the most important one. As soon as you have some form of array, the typing in php ends. I see this as such a short coming in the growing type system of php. Seeing a lonely array type always leaves me questioning simple things like: What kind of array is it, a list of strings, objects? Or maybe an associative array? Does it even hold items? Why are we here?
You mean like qt/qml? Due mind that even with those ui toolkits you will need to ship 'some' library. In case of QT it is not minimal at all. GTK can be more minimal but it still is significant.
Also there is tauri. Which doesn't ship a browser, but uses the platform native we view and is compiled while still having an amazing dev experience.