I see that sometimes too, but sometimes it works, idk why

Local stream extraction reliably works for me after a certain number of attempts at opening the video (sometimes 5, sometimes 15, it can vary). It has been like that on my selfhosted Piped instance using the desktop web client as well until the Newpipe/Piped team released a fix. The mobile app is still kinda broken and needs the previously mentioned annoying number of attempts