If he would have listened to Donitz and followed through on Plan Z, Germany would have conquered all of western Europe in a matter of months.
Which means he also would have controlled all of North Africa.
THEN...he could have gone against Russia.
Before Hitler invaded Poland, neither the French or British leadership had the stomachs for confronting him. Neville Chamberlain was content with appeasement. Hitler should have continued to allow them to "appease" him. Also, the prevailing attitude in the States at the time, was to let Europe deal with Hitler. We really didn't want to get involved.
Waiting just a few more years would have given him a MUCH larger navy. Donitz would have had HUNDREDS of U-boats to cut Britain off at the knees. The Bizmarck and Tirpitz would have been dwarfed by the 6 other H-class battleships that were planned.
The ME262 would have been fully implemented and deployed. Germany invaded Poland in Sept. of '39. 10 months later was the Battle Of Britain.
Waiting 3 or 4 years would have brought full units of the 262 into readiness.
That plane scared the bejeezus out of the allies.
The V rockets would have also been better developed to have been more than simple terror weapons.
Hitlers army was better. He had the best tanks and artillery. Waiting would have given him more. He also would not have had the huge losses of attrition, which is what doomed him in North Africa and Russia.
Also, Japan would not have attacked the US when it did, meaning they would also have had a much larger navy.
Lastly, the question that really needs to be asked is, if all of Europe fell to Germany in a matter of months, without the losses due to attrition and Hitler consolidated his power there, Did he really NEED to invade the US?
Basically, the whole idea of Axis vs Allies would have been different. As there would have been no allies.
It wasn't until AFTER Pearl Harbor that the US manufacturing might really came into play.
Imagine trying to bring that up against a military that was more built up to begin with and that also wasn't dwindled down by attrition. Also, Germany would then have all its own needed resources in its consolidated conquests.
Be careful, delaying the war would also have allowed the British especially to have improved their equipment. Two examples, the Supermarine Spitfire underwent testing and acceptance during the period between Munich and the invasion of Poland. IF the war had started even six month later SMS Bismark could not have sunk HMS Hood, because Hood would have been in drydock with her engine rooms in pieces (upgrades to her Armoring scheme was also planned).
As for the Me262, that plane was rushed from proof of concept to operational use due to desperation. several more years of development would have been of great benefit as among other problems it had was engine reliability (40 hours!).
A jet plane were demonstrated for Hitler in the 30’s but he dismissed the whole idea.