"@yausername put much effort into adding a fourth service to NewPipe: PeerTube. In case you do not know PeerTube, one can describe it as an open source decentralized video streaming platform.
NewPipe supports most of PeerTubes native features like searching, playing and downloading videos or reading comments. There is one structural point which differs PeerTube from all other so far supported services. Because PeerTube is decentralized, there are houndreds of instances available in the fediverse. We choose to use FramaTube as default instance, because the main organization behind PeerTube is the software developer Framasoft. NewPipe allows you to select the instances you like and add them to your personal list. You can switch between them seamlessly."
Search is in the top right, the magnifying glass. To get to Peertube, click the three bars on the top left. Select the dropdown arrow next to the word “YouTube”. I think the default Peertube option is called Framatube. You can change which instance you use by selecting the dropdown arrow right next to Framatube, but I think you can only see it if you add more instances.
To add more instances, on the main window (not the sidebar), click the button with three dots on the top right, then click settings, content, then Peertube Instances to manage them. Also, under the content settings, age restricted content is turned off by default.
I know you probably figured this all out, but for those who might not have yet.