I would let it play out untill Dunkirk before I strategical intervene, except the Military production.
Allready implementing standard systems and manufacturing as well as armour and ammo production.
Opel Blitz would be main deliverer of Opel Blitz Maultiers and trucks with modifications (Carden-Lloyd-Laufwerk) Halftracks like the SdKfz 250 and 251.
Mercedes would be Main Deliverer of Medic and Radio Trucks and Supply Trucks. (this effect will eliminate the abundace of vehikels and decrease the use of too many horses)
Tanks would only be developed with 7.5 cm and 8.8 cm guns, reconaissance with 2cm guns Standard.
Panzer II, III,and IV would still be manufactored but with diffrent options.
Panzer II would be produced as 10,5 cm Artillery “Wasp” and carrier and as Lynx Reconaissance Tank (by development)
Panzer III would be manuf. as StuG´s and StuG Ausf. H (further developments)
Panzer IV would be the main Tank with a 7.5 cm Gun and further developed.
-Also be used for selfpropelled Artillery Guns (Hummel with rotary turret).
(this will effect the abundance of the variety of tanks with diffrent calibers according to their Guns)
Further researches for better Tanks like the Panther would also be pushed.(Germans knew allready of the existens of the T-34 but simply underestimated it)
Chech Tanks would be raw modells for Tankdestroyers like the “Hetzer”
Speer would be immediatly in charge of the manufacturing in Germany.
Göring and other names would be fired or banned into exil.
The Wehrmacht would receive Luftwaffen liaison officer for better cooperating in battle between Tanks and Luftwaffe, so will the Navy. The Luftwaffe it self would be split in three diffrent parts and diffrent types of planes.
So is the first part for the Wehrmacht stocked with mainly Stukkas and Fighters, The Navy with Fighters and types for their specific use and the Luftwaffe HQ with Fighters , Strat.- and Tac Bombers.
(this will erase the missuse of Hierarchy and missunderstandings)
Ways of using the Fallshirmjäger later on would be as well researched.
For the Kriegsmarine (Navy) is planned to get 2-3 Aircraftcarriers with a hold of aprox. 30 - 35 planes to carry and another Bismarck class and named after Schlieffen and bigger subs with Snorkel.
Strategy: Taking Dunkirk by proceeding with the Armies with NO halt.
After that turing down south towards Paris as happend in WWII. Finishing the campagne of Greece and the Balkans.
Sending forces for Unternehmen Sonnenblume to aid Italian in the Africa campagne plus one additional Forces.
(England will not be invaded but cut off from all suplies by the wolfsrudel)
Unternehmen Brabarossa will not begin before spring 1942!
With the now manufactured Military armament and gained experience I could now strike into Russia and move torwards Moskow.
Then cease fire and get another trade with Russia by end of ´42 start of ´43. At this time England should be isolated and cut off by any supplies. If Russia or England should not surrender or sign a treaty, then another attack with the now more advanced technologies of weapon will do the rest.