There is no way to pay for adfree YouTube. In stream promotions are ads and it is impossible to pay to block them. Yea, sponsorblock is a great alternative.
Would you prefer Youtube to prevent creators from using sponsored content in their videos? If so, where would you draw the line? Just clear in-video ads? Is it ok to review a product that was provided by the manufacturer for free?
There's a lot of gray area which seems impossible to regulate.
Personally, if a creator serves too much sponsored content I simply wont watch them any longer. Fortunately it's not a problem among my Youtube channel subscriptions.
I don't know a good solution here. At a minimum, I'd like to see youtubers forced to label their videos with an "Ad" label if they are promoting a product.