Using hindsight, we can see that Germany in late 1940 was taking a series of gambles that were unlikely to win. It is argued in Adam Tooze's Wages of Destruction that decisions were taken at that time to invest in a massive expansion of production capacity to prepare for a coming air war against both Britain and America and chapter 13 is entitled "Preparing for Two Wars at Once". Thus Tooze attributes the Speer "Miracle" to those plants coming online as planned. He also notes that armament production for the invasion of Russia was limited because a quick victory was anticipated. This left the German Army short of transport and equipment and prevented them supplying, for example, enough anti-tank guns to their Italian, Romanian and Hungarian allies to enable them to survive Russian attacks. The use of steel for construction explains the paradox that Germany produced much more steel than the USSR but far fewer tanks.
The only plausible way to prepare for a war against Britain and America over 1943-4 without building a huge Luftwaffe would be to build a technologically advanced LW, most obviously with hindsight by giving maximum priority to developing jet engines and aircraft. The He 178 had flown in 1939 and there were already technical officers and officials who believed jet aircraft were the future, just few who believed that they could be deployed within three years (for example, "Engines of Desperation: Jet Engines, Production and New Weapons in the Third Reich" by Hermione Giffard has for 1941 that Helmut Schelp "viewed jet engine development as a long-term activity that would only come to fruition after the war"). Meanwhile others without a technical background, such as Udet, failed to see any of the possibilities over 1940-1 even when shown the He 280 in flight on 5th April 1941, showing that sacking Udet was an urgent necessity.
Giffard's thesis and subsequent book (neither of which I have read) apparently argues that the decision in 1942 to build jet engines with a minimum use of nickel and chromium was a choice rather than a necessity (see the thread at
Early German gas turbine development). Even if after the loss of Finland in 1944, Germany was very short of nickel, the situation in 1941 was very much better and it seems clear that the Jumo 109-004A could have been produced from 1942 to power the Me 262. I am not sure if more money and urgency could have brought the HeS 30 into production quickly enough give the He 280 a chance to compete. Historically it was running at full power by October 1942 (compared to December 1941 for the 109-004A) but it did have a much better power to weight ratio. If it really was as good as the data from Heinkel suggested, the next step should have been a scaled up engine to compete against the Nene.
It is probably not enough to just talk about money. We need to cancel projects to free engineers. Obvious cancellations with hindsight include the A4/V-2 and the Me-163 Komet. We can also forget the BMW-802 and 803, the DB-604, 606 and 610 and the Jumo-222 and 223 (I must confess that I suspect that the BMW-802 and the Jumo-222 could have been sorted out but not in time. The 802 was the very first engine with variable valve timing and the Russians produced a successful engine using the 222 arrangement
Dobrynin VD-4K - Wikipedia).
However, the V-1 will get maximum priority because it is the ideal revenge weapon if it can be ready for 1943.
I am also going to support Hitler's idea of using jets as bombers. Me 262s or Arado 234s carrying a Bombentorpedo such as the BT-700 could have made an invasion of France very difficult.
The Me 262 and possibly He 280 might have benefited from the Askania EZ-42. An early version the EZ 40 was tested in a Bf 109F, so presumably in 1941-2, and the technicians who spoke to S/LDR Fisher believed they could have produced a working sight earlier than late 1944 and perhaps even before Britain
BIOS-67. Is it too much hindsight to also develop the R4M early?