I'd be careful about contradicting the current RDA based on just tentative evidence. 4000 mg quite a lot more than the current RDA of 2300 mg and it tops the current intake of Americans by 700 mg.

Here's a 20-year trial: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5098805/

" This study, with carefully characterized measures of sodium intake, found an increased risk at high sodium intake and a direct relation with total mortality even at the lowest levels of sodium intake. Overall, these results are consistent with a benefit of reduced sodium and sodium/potassium on total mortality over a period of over 20 years. "