I don't have other solutions for you. It's not easy to make a universal app for all screen sizes and aspect ratios.
Scale Outer method allows to make layouts that are "compatible" with different screens, but it's not perfect. You need to deal with the background and off-screen objects etc.
If you don't like this, you can simply design different copies of the same layout for different aspect ratios (4:3, 16:9, 18:9 etc.), or even build different apps for different screens.