A more measured approach along multiple, logistically sustainable axises to avoid ripostes over the winter.
Yep
Bingo
There was no silver bullet to bring victory earlier. A few of the improvements possible.
1.Securing the Scheldt in September while the German 15th Army was still moving & less organized. That opens Antwerp earlier, perhaps in early October, but certainly by late October.
2. A more limited or multi stage attack towards Arnhem, or another route into Netherlands.
3. Priority to building up forward logisitcs in 12th AG area.
4. Increasing pressure in 6th AG area to draw German reserves to the south and threaten a Rhine crossing from Straussberg southwards. 6th AG had a good logistics situation & giving it more responsibility while 21 & 12 AG support was rebuilt would have been helpfull.
5. Higher priority to destruction of the German railroads. It took just a few months for the Allied air forces to trash the Italian railways in Operation Strangle, and for the similar air campaign to work in NW France. OTL the Allies did not start a full blown anti transport campaign against Germany until January 1945. Redirecting the 8th AF to assist 9th AF & 2d Tactical AF this in August or September could have created a transportation crisis in western Germany by December, vs March 1945. Maybe sooner.
All that combined would have weakened the German field armies, reduced offensive capability, & accelerated Allied offensives in the winter of 1944-45.
1. Capturing much of the 15th Army would also be an advantage - also very little was done to stop the mini Dunkirk
2. A Smarter Market Garden would certainly work far better than OTL - coup de mains on the main Bridges and more solid human intel - through Special forces team's and/or having rebuilt the Dutch resistance.
3. 6th Army can be supplied from the south as much of the infrastructure had been less damaged and 2 major ports were taken intact - and they have Audie Murphy.
I agree with 12th Army getting the lions share of the supplies from Normandy but only after Antwerp is opened for Business.
Should A Market garden go ahead...possibly but with perhaps as you say goals directly linked to the opening of Antwerp as a supply port.
I would leave any encirclement operations post Normandy - such as laying siege to various ports where ever possible to recently formed French formations or Green US Divisions recently arrived from the States - freeing up more of the experienced divisions to push on to the Rhine, earlier.
4. Regarding 6th AG moving up faster - do have a care - as it was some of its sub formations suffered more casualties than any other US units (3rd Division suffered 27,000 casualties in total during the campaign) so its not like they were not fighting very hard.
5. Rail roads and Canal links and an earlier greater effort against POL.