2. It's some sort of bug I think in the theme library which we're using for UNA mobile app, but you can try to play with this code (particularly with setBarStyle), by removing functionality for dark//light mode support and make it static, so it should work then:
const isDarkMode = useDarkMode();
var sBarStyle = 'dark-content';
if (Platform.OS === 'android' || isDarkMode)
sBarStyle = 'light-content';
if (Platform.OS === 'android')
To make PUSH working you need to open OneSignal account then setup it properly for Web Browsers, Android and iOS[if needed] in OneSignal - then have necessary instructions on how to do it. Then specify OneSignal App ID in UNA and mobile apps.