That is an interesting question, though you are probably right. The Court has not asserted that abortions per se are a violation of the Constitution, but that Roe incorrectly affirmed that there was a right to abortion. Presumably there are laws that could be passed (e.g., red-haired persons may be shot on sight) that would certainly be found to be unconstitutional. In the case of abortion, the Court could find a right to life for the unborn and invalidate any law Congress might pass that guaranteed the right to an abortion.

Bottom line, I don't think one can assert without fear of being proven wrong either that Congress can confer a right to abortion or that it can't.