If dietary salt causes high blood pressure, then reducing salt intake should lower blood pressure. Yet, for the vast majority of people with hypertension, restricting salt has marginal benefits at best.
Why? Because the root cause is NOT salt intake. One of the main drivers of hypertension is salt and water retention by the kidneys, which is abnormally high in people with chronically elevated insulin from excessive carbohydrates intake.
Reducing carbohydrates will have a much more drastic effect on lowering blood pressure, by reducing salt and water retention.