According to the video you linked, AdSense and in-video ads are basically tied for income (26 and 27% respectively). Both of those are significant sources of income!
In the video I linked, "Sponsored projects" is a type of in-video ads, where they build a particular PC and the video is sponsored by a hardware company, so the total for all types of in-video ads is 41% vs 26% from AdSense.
For smaller Youtubers (LTT is a very large channel) the gap between AdSense and in-video tends to be wider. I don't have hard data on this but it's the result of talking to several youtubers in person. If someone has the data, it would be cool to share it here.
For smaller Youtubers (LTT is a very large channel) the gap between AdSense and in-video tends to be wider. I don't have hard data on this but it's the result of talking to several youtubers in person. If someone has the data, it would be cool to share it here.