1) Risaala Al-Yemeniyya is Iggeret Teiman, not Dalalat Al-Hai’irin – aka Moreh Nevuchim. Go learn Arabic. And yes, Rambam’s opinion does in fact matter, because you keep on invoking Rambam to back your case, when that simply isn’t so.
As for other Poskim, it may be the Ashkenazi position that the rulings of previous leaders must be taken into account. But it is just that, an Ashkenazi position and tendency. It is not a Sephardic position at all, nor it is an absolute amongst Ashkenazim. In fact, because there is no Sanhedrin and more often than not there is no central bais din in any given city, no Rav has binding authority. Therefore, we can respectfully question and reject a previous court’s ruling with justifiable reason for doing so. If you bothered to read that acutal works of the Rambam (and Ri Megash, and the Rif) you keep on trying to use to back your case, you would know this.
Which leads to my next point.
2) Re Aggadeta. This actually matters, but you’re not listening so we’re done here.
3) You’re not listening again. I’m saying that R Teitelbaum did not have any binding authority over anyone other than his community. Period. End of discussion. He did not. No one recognized him as having any binding authority outside of his direct followers and those who joined his “Chassidus” in the wake of the Holocaust after their religious communities were annihilated by the Nazis YMSV”Z. He didn’t even have binding authority within his city of residence, much less in Hungary, Eastern Europe, Ashkenaz or all of Am Yisrael.
Kindly stop with the nonsense that a R Teitelbaum had absolute authority over all of Am Yisrael to issue his ruling when he did not.