Just gotta respond.
Let's go through your OP point by point.
Say you got a Junkers rightist authoritarian regime still wanting to see if they can beat the UK and French head to head without the pesky USA coming in at an inopportune time to spoil the fun. They know they have to pick up the pieces from the Versailles Treaty by economically growing their way out of it to where reparations go from ruinous in 1919 to loose change by 1930.
Instead of Nazi racial politics, they're more motivated toward Germany getting its due, are economic realists, and tolerant, if somewhat contemptuous of non-Aryans. Jews, Poles, and other Auslander may be accepted if they served in the military and spoke German and so forth.
For these men, the Soviet Union is what nearly won them the war and an interesting social experiment. Bonus points if the Mensheviks and SR's take over and pose little external threat.
An interesting POD would be German expressions of sympathy for the Soviets recovering "Russian" territory robbed of them by the Treaty of Versailles creating Poland out of whole cloth. Never mind the treaty of Brest-Litovsk!. OK, so it's ASB.
Basically, German chemical companies set up operations in Baku and various other areas to get Soviet oil and other minerals flowing west, in exchange for German machine tools, locomotives, and so forth.
A key issue is no active official harassment that doesn't spook Central European intelligentsia to flee for the exits. So, they could have a significant lead on the UK and the US in atomic research, among other areas.
I'm trying to think of some PODs for Germany NOT going as militaristic as the Nazis OTL. They could've gotten the Danzig Corridor, the Sudetenland, and Anschluss with Austria diplomatically, going for a Mitteleuropa tied together in a free-trade zone with Poland, Hungary, Czechoslovakia, and Romania as members. Holland might play along.
Belgium won't without a really serious charm offensive from the Germans
apologizing profusely for the unfortunate exigencies of war, paying extensive reparations and still I see a tough road ahead.
We talk a lot about how Germany's maritime tradition was definitely sucking hind tit to the army. As far as military emphasis and budget, you're right.
However, the Nazis felt the Kaiser's whole trying to compete with England in naval fleets was a chimera that diverted too much materiel and money from in their opinion, the decisive military arm- the army in WWI.
However, the German merchant marine IOTL was nothing to sneeze at.
I won't pretend Hamburg or Kiel or Rostock were the equals of Liverpool, Belfast, or London docks, but they weren't chopped liver.
Say the German shipyards develop a highly successful class of freighters, tankers, and such like South Korean yards do now as contract yards for the world's merchant fleets to keep shipyard workers busy and getting plenty of folks maritime design, operations, and logistics experience.
Bonus points if they get the Dutch yards and ports to work with them to expand capacity and tie them into their rail network? Of course the Rhein tugs and barges do a lot of work moving cargo as well and could work like the Kaiser yards did shuffling pieces back and forth along the Mississippi as they did with the Liberty ships to be assembled or completed on the coast.
A little tough to make happen during the Depression but compared to the many public-works projects, not entirely ASB that might actually earn a little coin. Same for Lufthansa developing a respectable civilian transport fleet, though IOTL zeppelins were supposed to be the prestige arm.
Of course, w/o all the kerfuffle with Nazis, the Germans can make helium-filled zeppelins for prestige passenger and cargo transport traffic. Basically, Germany sells itself as the indispensable middleman that makes everything happen with style. Of course with this emphasis on trade and relatively harmless civilian tech going on, you might ask what casus belli might exist?
France is still massively pissed about WWI. It was an economic and emotional catastrophe that killed 20% of military-age males, thoroughly screwed up the most economically vital areas in the north, etc. Sure, they saved Paris, by emptying the villages and towns in the rest of the country with knock-on effects on agriculture and commerce.
The French could feel betrayed by the Russians and chumped by the British. Never mind all the BEF casualties growing poppies in Flanders. How they feel about the US could be some hard feelings re: Wilson meddling to keep Clemenceau from consigning Germany to penury and all the debts owed to the US piled up during WWI used to tell Clemenceau to back down.
Were they a country invaded America felt a historic debt to repay in blood or just an investment?
It depends on who's shouting loudest when mass unemployment and dislocation hit the French economy.
If this Junkers industrial technocracy gets rolling in Germany, France is going to be left in the dust and clinging to its colonies to feel strong.
Britain could also get outcompeted economically and feel a little butt-hurt that Germany went from starving to suave in twelve years with a huge trade-bloc sharing resources and integrating rapidly, while they struggle with WWI war debts and creeping obsolescence in many areas and bitter labor struggles making it difficult to upgrade facilities and turn a decent profit.
Just a few thoughts toward what kind of politics, economics, and technical developments would allow that to go from a near-run fiasco a la OTL Battle of Britain to a serious battle of maritime and aerial equals in 1940.