This article has interesting points. The whole debate skips over being Sephardic.

according to Yosef Carmel, an Orthodox rabbi and co-head of Eretz Hemdah, a Jerusalem-based institute that trains rabbinical judges for the Rabbinate, this is a misunderstanding of how the DNA testing is being used. He explained that the Rabbinate are not using a generalized Jewish ancestry test, but one that screens for a specific variant on the mitochondrial DNA – DNA that is passed down through the mother – that can be found almost exclusively in Ashkenazi Jews

https://www.theguardian.com/lifeandstyle/2019/jun/12/what-does-it-mean-to-be-genetically-jewish