I am having a difficult time finding anyone with an answer to my question below, mostly because my access to Talmidei Chachamim is limited because of the community in which I live. I daven in a shul where at least half of the members daven nusach Sephardi, while the other half davens Ashkenaz. When individuals say mourner’s Kaddish, they are allowed to use their own nusach, and we have both types of siddurim. However, the official nusach is Ashkenaz. My wife and I underwent conversion together a little over a year ago through an Orthodox Beit Din. I wanted to observe nusach Sephardi, because I feel a greater connection to the Sephardi minhagim than the Askenazi minhagim. However, it was suggested to me to follow the official nusach of the shul and daven nusach Ashkenaz. Unfortunately, as time goes on, my desire to follow nusach Sephardi grows stronger. Short of moving to another city with a Sephardic shul, would it be a violation of Halacha to follow nusach Sephardi, at least privately? Would it be proper to change my Tzitziot, Mezuzot, Tefillin, to Nusach Sephardi?

You can switch to Sepharadi Nusach, and of course change Tefillin and Mezuzot, if you like it is possible because the reason we do not change is "Lo Titosh Torat Imecha", do not leave the teachings of your mother, and it doesn't apply to our case. Rabbi Chaim Katz