iPhone 15 Pro Max screen rotation and dark icon issues after iOS 26 update

I am on iPhone 15 Pro Max. Screen do not rotate automatically on apps like Youtube and several other streaming apps. I have to choose full screen manually and even like that if I rotate the phone 180° it looks upside down. Also apps icons look like they are on light theme mode and I have choose for the phone theme to be dark (I have try to toggle theme and I have restart the phone several times).

[Re-Titled by Moderator]

Original Title: After iOS26 portrait orientation wont rotate (is off) and Icons dont get dark theme