After I made the post I remembered they already do it. Brands can pay to sponsor existing videos that put them in a good light. These recomendations do have an [Ad] tag, but the extra views and impressions are allow to feed into the algorithm which then doesn't have to maintain the [Ad] tag going forward:
https://support.google.com/google-ads/thread/10007177/using-...
Re:On YouTube’s recommendation system
by frosted-flakes on Friday September 17, 2021 @10:10PM
(#28572950)
Occasionally I will see a "Rising Creator" section on the Explore/Trending page showcasing a single channel. This channel typically has less than 5k subscribers and posts regularly.
We'll see though!