Using my Vidgo credentials, I'm able to log into the NFL app (Fire TV) and watch the Channel, but if you're saying that the NFL is unviewable/recordable in Channels DVR because of encryption, how long will it take before other networks do the same thing? OTA channels around the country are adding encryption to their ATSC 3.0 signals so I'm sure streaming networks will be looking at doing the same thing to their TVE/Go sites so they only work with their own app.
My Channels DVR subscription just renewed so I have a year to find out how the Channels team is doing to deal with the problem. Personally I love how Channels can merge OTA and TVE sources into one guide and DVR, using one app, but if other networks do the same thing the NFL Network is doing and Channels can't handle the channels we watch, I may have to go back to the crummy guide and recording app for my streaming service.