Could new naval treaties stop the 1940s arms race?

Would unsustainable costs lead to new naval treaties in the mid- or late 1940s?

Probably not; low trust, unreliable dictatorships, and a fast qualitative technology race make enforceable limits too risky.

The major powers are unlikely to restore treaty constraints after escaping them. Any agreement must somehow bind Hitler, Stalin, Mussolini, and Japan at a time of declining trust and growing competition. Rapid qualitative change also makes a limit dangerous because a rule written around one generation of ships or weapons can advantage the state furthest ahead. The interwar treaties worked as well as they did partly because the signatories still shared a significant post-World-War-I basis of trust. Once that foundation and the technical status quo disappear, cost pressure alone cannot restore arms control.