According to Sefardic halaha laws: does a kiddish cup need to be silver? can’t be made of wood?
A kiddush cup can be made of wood or any other durable material.
It is better to refrain from a disposable cup.
A cup used for Kiddush should be made of durable material (Iggros Moshe, Orach Chaim 3:39), out of respect for the Kol Shel Berachah, so that a disposable cup is not lechatchilah. See also Shut Minchas Yitzchak 18:23, who questions whether a disposable cup can be considered a keli for this purpose.
Certainly, any durable material is valid – though some prefer silver as a hiddur (beautifying the mitzvah).
There is no difference in this matter between Sefardi and Ashkenaz custom.