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}
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.