Sponsorblock theoretically exists

In its current form, it would only work if each video had the ads injected at the same timestamp and with the same duration everytime, which I find unlikely.

It would have to implement some dynamic behavior. It is however in at least some countries required to visibly and clearly mark ads, so a check for that marking could possibly be implemented. But that's more of a thing I'd expect uBO to do instead of Sponsorblock.

Going by recent internet history, every anti-adblock measure will have its according anti-anti-adblock measure within at most a few weeks by now. That's the beauty of community-driven open source projects.