I don’t see anything like that on https://youtube.com/premium

Seems to still being trialed in only a few regions. It's No ads during videos (still display ads during search, etc.), except for shorts and music videos for 6€/m. Without all the other premium features

I would guess that music producers are demanding unreasonable amounts of money per view, so carving them out of the equation is a fine trade IMO

Yes but leaving out all other features and showing display ads for a still steep price of 6€ is not so great.