How would a successful X-1 change treaties and World War II?

If the Royal Navy liked X-1 and continued developing cruiser submarines, how would that affect naval treaties and World War II?

A successful X-1 could make large submarines a treaty force category and provoke earlier ASW investment, weakening Germany's late-starting U-boat campaign while creating stronger Italian and Japanese long-range threats.

X-1's reliability is the first link in a much wider institutional counterfactual. Operational success would give Britain a reason to preserve and regulate large submarines instead of seeking their abolition. Treaty ratios would then encourage several navies to build cruiser-submarine forces while potential opponents funded escorts and doctrine in response. By 1939, the most consequential change may be a mature Allied ASW establishment waiting for Germany, balanced against more capable Italian and Japanese ocean-going boats.