I cannot link my iPhone XR to my Q80 65. They are both on the same network. I can link using YouTube tv code, I find reentering the code a bit tedious. We have 4 iPhone users in the family, none can link.
Do you have the smart things app installed on your iphone? I believe the easiest way to sync your phone seemlessly with your Tv is by setting up the Smart Things app and interfacing it with your phone that way. Please let me know if this is of any help to you.