always view the Soviet naval plans as best possible scenario for Germany, puts USSR on collision course with GB, Japan ... anybody else? ... Turkey, probably Iran for warm water port?
of course it is ASB or nearly for Germany to collaborate with USSR for more than short term objectives, but added qualifier "nearly" since the Soviets could provoke a shooting war with Allies if they launched so many battleships.
so instead of building two aircraft carriers and/or Bismarck and Tirpitz the Germans build battleships for sale (barter) to Soviet navy? what could they have gotten for those?
Random raw materials which Germany itself does not posess, but more importantly is that building the ships puts German shipyards to work, gives them experience in construction, gives the engineers time to work on their plans and refine them for future German warships etc.
Building ships for the Sovet navy might be a bit too much of a provocation though, maybe they could do it for the Chinese one instead?
the whole point of the exercise from German point of view IS provocation, to get Soviets (Stalin) to waste time and resources on navy instead of say ... tanks? gain raw materials for themselves and provoke the Allies into striking Soviets.
that was whole point of "offering" Iran, India, all points south in historical Axis talks, to have the Soviets fight Great Britain.