I was under the impression that they could ONLY use the goal cam because some venues don't have TV broadcasts.
That's why they couldn't overturn a no goal for us earlier in the year, because it couldn't be over turned by just the goal cam.
My last dataflix was last season, and I know it made it full screen, because I had it on my TV, as well.
You could try "Alt-Enter," since that is the key-command to go full screen.