There's a difference between product placement and intrusive ads that interrupt content for minutes at a time. YouTube Premium customers paid to get rid of the latter.
YouTube Premium customers paid to get rid of ads placed by YouTube. A simple solution for channels that embed ads in their videos themselves (or have any other kind of content that you don't like for any reason) is to simply unsubscribe.
Yes but that is like not visiting a site after you found out it uses tracking or like peeing in your pants for warmth. It only work if you never see videos you haven't already subscribed to beforehand.