I think a better strategy for Hitler would have been to maintain his alliance with Stalin, at least in the short term.
The forces used in Barbarossa could obviously have pretty easily conquered North Africa and swept all the way to the Persian Gulf. Stalin gets Romania, Bulgaria, Persia and Turkey. The Med becomes a German lake. Hitler’s fuel problems are over.
Spend perhaps five years using his newly acquired resources and the industrial power of all of Europe to build up an army and possibly even a navy that would allow him to quickly crush Stalin when he finally attacks and then turn on the West. World domination.
I agree. If Hitler hadn’t wasted his best divisions by turning on Stalin he would have been in an incredibly strong position for tying up fuel supplies and the Mediterranean.
The biggest obstacle for his long term goal was Nazism itself. It was essentially a ruthless criminal enterprise operating as a political party. The SS exemplified this, being the armed wing of the Nazi party rather than part of the regular German military. A documented act of cruelty against the German people had been a requirement for joining the SS. A regime that operated like that simply couldn’t last. Eventually your home grown enemies will find a way to turn on you.
Dr. A. Roberts presents Why Hitler Lost the War: German Strategic Mistakes in WWII; speech to the U.S. Army War College:
https://www.youtube.com/watch?v=5agLW7fTzBc