I see there is a lot of content posted on lemmy that points to different instances of peertube but I often find it difficult to find it within my instance.
While this is not a solution to the search problem as such, I can highly recommend the Firefox-addon Peertube Companion - it can be set up to automatically re-direct you to your home instance, from any link to a video on another server, that can also be viewed from home. That makes it easy to quickly engage with content from your PeerTube account - like subscribe, like, comment.
As a bonus, it can also re-direct to PeerTube, when it detects a YT video being mirrorred on PT.