Drinking an additional reviis for makom seudah isn’t a kula though
It is according to many.
https://www.star-k.org/articles/kashrus-kurrents/649/the-halachic-guide-to-kiddush/Seudah
a. Ideally, the seudah consists of bread. Typically, following Kiddush one washes and recites Hamotzi on lechem mishne (two loaves). This constitutes Kiddush B’Makom seudah, as the seudah follows Kiddush.
b. If one does not eat bread (e.g. at a simcha in shul after davening), one may eat a food containing chamaishis minei dagan (five special grains including wheat, oats, etc.) upon which the brocha of Mezonos is recited. Ideally, the food should be pas haba’a b’kisnin (e.g. cake, cookies or crackers). However, the “seudah” may consist of other Mezonos products, such as Yerushalmi kugel or pasta salad. In these cases, a regular seudahs Shabbos with lechem mishne must be eaten later.
c.
B’sha’as hadechak, if one is ill and cannot eat grain products for Kiddush B’Makom seudah, one can drink a revi’is of wine or grape juice to fulfill this condition.
