Tofu is often used as a meat replacement and is Nova classification 3 at most.

I agree, it is used in place of meat, but I think that it is not usually intended to mimic meat. For example, I think that few people would claim you could use tofu as a drop-in recipe replacement without affecting flavor, whereas meat replacers like Impossible are intended to be able to do exactly that.

TBF, the original post used the precise phrasing "plant based meat replacement", which IMO covers this like tofu as well as impossible burgers.