Replacement for Unity's built-in resolution dialog (aka Screen Selector) that was removed in Unity 2019.3. Works both up front (simply make it the first scene) and as a popup dialog (default key: ESC). Intended for development / testing purposes but can also be used in production.

Add this dependency to your manifest.json located at /Packages/manifest.json:

{
    ...
    "dependencies": {
        ...
        "com.sitterheim.unityresolutiondialog": "https://github.com/sitterheim/UnityResolutionDialog.git#release/stable"
    }
    ...
}