Yeah, I'm confused about what people even talking about with logins. That's not a thing. There's no option to login with Google/Youtube on Newpipe, and that's by design. The value proposition, in addition to being a wonderfully designed, lightweight app, is the ability to subscribe, follow channels, view, download video without any Google/Youtube connection.
I wasn't aware of that at the time. Having used it a bit now, some of the choices do baffle me. It has such wonderfully granular control over bitrate and background behavior, but no option to play the videos you tap on without having to hit a separate "play" button after the video is open? Very odd.