Came here to post this request myself, and found you beat me to it. 🙂 So I'll just add my experience for context:
There are a lot of reposts on YouTube. For example, if I'm looking for trailers for a new video game, I generally want the official video, not a re-upload from a gaming news site, secondary promotional video from a partner, or commentary/reaction videos. Consider this screenshot of video results for Final Fantasy VII Rebirth:
Here are three videos from three different sources. Only the first one is from the primary source, which is the official Final Fantasy channel. The second is from PlayStation, and the third is from IGN. This is not clear from the presentation in Kagi.
I noticed that some videos do already display the account name, so I guess this is either a bug or an API limitation like the one mentioned here about the upload date: https://kagifeedback.org/d/1849-youtube-not-all-videos-have-date-listed
Fingers crossed that this can be enabled for all videos!