Nope, I do not consider an unrecognized sample as copyright infringement. Or, I don’t believe it should be ruled as such by the courts.

If you can’t reasonably recognize the source material, and it’s so different that only AI looking at bits could identify similarities, that doesn’t cross the threshold in my opinion.

I actually don’t think most sampling should be considered infringement, assuming the new song is actually a new work.

It’s all about how transformative the work is.