I had been getting errors for a long time whenever trying to play/download videos, but turning off my VPN (I use NordVPN) worked instantly! I’ve had extremely consistent performance since doing this.
Now I just pause my VPN when I’m at home to download videos, and then I turn it back on when I leave and can watch the downloaded videos anywhere with my VPN on. Long live NewPipe and gosh bless the developers for this amazing product! Such a simple fix on my end.