Given the acidity of the wort, any basic buffer should work, even chalk. A tougher calculation is determining how much to add to avoid overdosing.
Its too bad you've already added the sodium to that Gose. Sodium chloride is best added to the beer after fermentation and should not be in the wort or beer at high concentration to avoid upsetting the fermentation.
I wonder how much sodium it takes to interrupt fermentation. On a very early AG brew I accidentally left my digital scale set to ounces instead of grams and added like an ounce of sodium (and ounces of the other brewing salts) to a five gallon batch. It fermented perfectly fine but it was an undrinkably salty brew. Made a great marinade.
I only added 21 grams, so I don't have any concerns. I can always add back. Wort doesn't taste all that salty so should be ok.