I don’t see what your problem is. You found a piece of secular scholarship that is not like Rashi but is like RaMBaN and Ibn Ezra. Either you can say that metzius is a rayah to Ibn Ezra, or you can say rashi is a raya against the secular scholarship. Both mehalchim have ample precedent. Either way, you have a nice dvar Torah and there is no reason to get upset.
