We wouldn’t say the Rishon is wrong,although we c/would call
them aberrant
Why not just call them “a be normal” and be done with it.
You are trying to have your cake and eat it too, and it isn’t working.
Either give the Rishonim full deference, and allow for Shittos like Rabbanu Avraham Ben HaRambam, Iben Ezra, the Rambam himself, etc. and that people should follow them. Or admit that they are sometimes wrong regarding secular knowledge, just like Tosfos argues with Rashi regarding the direction of the Tigris river (which we can see which direction it flows), or Tosfos was deficient in mathematical knowledge of the Pythagorean Theorem.
By being “Poseach al shtei si’ifim”, you make no sense.