I have unlock Ultra, one tv when I screen mirror it just shows wallpaper, second TV will mirror but black screen no viedo from Netflix but have sound, any answers. Note 10 plus works fine. Ultra not so much.
What type of TV are you using?
Are you using the Smart View feature to screen mirror to your TV's?
What type of TV are you trying to use Smart View to cast to?
So HBO, Netflix, Hulu, Disney ect have some kind of data protection to not allow streaming I guess, those need to be cast to tv chromcast or Firestick. SONY TV does even mirror the screen at all just wallpaper of the Ultra.
Netflix also has data protection in regards to streaming and require a special connection. It would be normal to see the screen of your phone when screen mirroring. Functions available would be playing home videos, photos, slide-shows, music, etc.