Screen Mirror / AirPlay Not Working.

I have followed every step suggested by the forums here on Apple support and from third party website, and my phone still won’t let me use screen mirror or airplay.

I have an iPhone 8, it’s fully up to date as is my Westinghouse Roku TV. They are on the same Wi-Fi, all permissions are enabled including screen mirroring and AirPlay, but it still is not working. I have followed every step already suggested on other threads. I have even tried using the HomeKit feature, but when I scan the QR code, my iPhone says “no user data found”.