I think the Pri Megadim is fine and you are remembering the Ran incorrectly. He says that Bitul is universally accepted to require Hisnagdus. According to Rabbi Yehuda, it must be conflict in Metzius; therefore, Min b’Mino is never Batel. According to the Chachomim, even Hisnagdus in Din is sufficient to effect Bitul. However, the contrast must be extreme, and Davar she’Yesh Lo Matirim is too similar to Heter to create sufficient opposition for Bitul. Certainly, the Chachomim agree that Hisnagdus in Metzius is Kal v’Chomer sufficient for Bitul.
Also, my point with Rabbi Akiva Eiger was that his reason is NOT “nothing could go wrong”
Also, once Chazal forbade Bitul Issur l’Chatchila, we cannot dismiss a d’Rabannan just because we think thmotiveve is not relevant. So, the Sevara is not enough to make it Mutar.