Here you are right. Newpipe seearch is not good. You can't find many as many videos like youtube. But on android I am limited to some channels and playlists. For finding videos and scrolling through I use PC. Newpipe is only for downloading and watching channels I have subscribed or if someone shares any link.their search engine is extremely weak (unable to list the majorly of videos and channels).
Newpipe misses a lot of videos. You can try to search anything like "ublock origin". It will show you only top 10-12 results of youtube. While on you tube you will find lots of videos for same keyword.Not sure about the search engine quality, I don't subscribe to many channels, but if you could list a few that NewPipe doesn't recognize, I could help to improve their product.