I remember reading in Japan's guidelines allow up to 12 grams of salt daily for adult males (4800 mg sodium) who do manual work (i.e. sweat).
The document on this site:
https://www.fao.org/nutrition/education/food-dietary-guideli...
recommends a broad limit of 10 g of salt (4000 mg) per day, claiming that the average consumption in Japan is 12.7 g (based on some pretty dated 1998 study). (Unfortunately, the document pays lip service to the same misconceptions: too much salt causes high blood pressure---and stomach cancer, to boot.) The recommendation is still way above the USDA's crazy figure of 2300 mg.
Anyway, pick a country that isn't generally stupid/corrupt about food and health, and use their recommendations.