How giant Soviet cruiser submarines could reshape Western fleets

What would happen if Stalin ordered gigantic cruiser submarines instead of conventional cruisers?

They would likely trigger a submarine-cruiser building race and could keep Western heavy surface ships in service to counter them.

If Stalin ordered the proposed cruisers as gigantic submarine cruisers, the result would probably be a submarine-cruiser construction race rather than an isolated Soviet program. A later follow-up suggests that the threat might keep Alaska-class large cruisers or comparable heavy surface ships in service as counters. The idea is explicitly counterfactual, but one unusual procurement choice could provoke a different force structure on both sides.