Does gamepass show live games? I thought they only showed them once they had been completed
If you are using US version of Game Pass, no. You have black-out rules and games are not live streamed due to the lucrative deal that the NFL has with Sunday Ticket in the states (which goes until 2021 or 2022).
The International version of Game Pass is completely open. No black-outs and you can watch every game live. The price (at least in Germany) is $179.99 for the whole enchilada (preseason, regular, post season, combine, draft, archived games, etc). You'll need to use a VPN (I use Strong VPN and bounce off servers in Berlin) to access and create an account with
https://www.nflgamepass.com/en Start a 7-day trial just to make sure it works for you first. You'll need to use the VPN just to log in each time and then you can disconnect after establishing the connection... or just leave it be (I don't suffer any speed loss leaving the VPN connected). Boom. Done. You'll never go back to Sunday Ticket or watching it locally anymore.
Just google "Game Pass International" if you want more info. I promise you, it's extremely easy to set-up and you'll wonder why more people don't know about it.