Do you have a link to the main tracking issue with NewPipe? I tried to look through their GitHub repo, but most of the issues I saw were about the 59-second bug, or they had been closed as duplicate without linking to the duplicate issue.
I have a 1.5 hour commute, and watching downloaded videos on NewPipe is a major part of my strategy for getting through it.
I don't think that's the right issue. The behavior I see is a network error toast message that says check the notification for details (with no notification). This issue says the behavior is the "content unavailable" screen, which I don't see.