To put it shortly: Yes, the USSR would most likely have occupied all of Germany, and gone further still had not the Allies met up with them.

To not put it shortly: Lend-Lease has been widely exaggerated. In an interview regarding Lend-Lease, David Glantz said that "if the Western Allies had not provided equipment and invaded northwest Europe, Stalin and his commanders might have taken twelve to eighteen months longer to finish off the Wehrmacht,", and later "the result would probably have been the same, except that Soviet soldiers would have waded at France’s Atlantic beaches rather than meeting the Allies at the Elbe.”

While the Soviets received a great amount of supplies this only constituted a comparatively minor percentage of their own production, as you could see in David Glantz's "Myths and Realities". And war isn't a simple calculation of supplies or of anything else. Soviet doctrine was very sophisticated and after the emergence of very competent generals like Konev and Rokossovsky the Red Army became (probably) the most professional and effective army in the world. To say that Germany lost because of Lend-Lease is both historically shaky and a lame cop out, the sort of unconvincing excuse the German generals would come up with to pretend they were better than the Russians despite losing.

Glantz didn't make any attempt to imply anything in "Myths and Realities", he simply posted a table showing that Lend-Lease did not make up more than about 10% of any Soviet material other than trucks, which was based on the Russians’ own estimates. Glantz is hardly alone in this conclusion, Norman Davies concludes the same in "No Simple Victory", and the Soviet historians themselves, despite what Krushchev and Zhukov said, have consistently denied that Lend-Lease was decisive.

Most of the Russian raw materials and weapons came from domestic sources. It is very unconvincing to say that the 10% of food stocks provided by the US won the war for Russia and not the 90% of food the Soviet Union produced itself. This is a bizarre calculation.

The most important contribution from Lend-Lease was in the form of locomotion, which isn't necessary to conduct war. Walter Dunn has demonstrated that even with trucks the Red Army was still heavily reliant on horses and oftentimes horses were more useful than trucks in areas with heavy snow and poor infrastructure, which was a lot of the area in Eastern Europe.

The scholarly consensus is that Lend-Lease was not required for Soviet survival, especially during the first eighteen months of war, but greatly enhanced Soviet offensive power thereafter. For example Cathal Nolan in the "Encyclopedia of World War Two" suggests that the Soviets would have won anyway but it would have taken them longer.

There are certain categories where Allied contributions were very important, particularly in rare metals, but this doesn’t mean the Soviets couldn’t have done without them.

Because, for example, the Germans were perpetually short of everything, Adam Tooze and Williamson Murray believe the Germans were less prepared for the Second World War than for the First, and indeed the 1917 production of gunpowder, for instance, was not reached by Germany until 1943 or 1944.

There’s also the example of the British, who received far more Lend-Lease deliveries from the US and achieved far less with them. And it is rare to find someone who argues that the British would have been crushed without them, a question sardonically posed by Norman Davies in his article "How We Didn’t Win the War, But the Russians Did".

As Randell Wells Jr. points out in "Tearing the Guts Out of the Wehrmacht", by 1943 the disparity in losses between the Soviets and Germans had become much more narrow. And losses in the first years were inflated due to large numbers of captures, especially during Barbarossa when the element of surprise was entirely on Germany’s side and the direction of the German advance was guessed wrong by STAVKA, who massed south of the Pripet Marshes when the Germans struck with their main force in the north.

The Allies could never have landed in France or Italy if the Russians hadn't destroyed so many German formations and forced most of the remainder to face them.

Bagration and things like the Vistula-Oder and Kishinev-Jassy offensives witnessed the Russians break the German lines in multiple places and encircle numerous German formations, wiping them out from Germany's OOB. During Bagration German Army Group Centre was completely wiped off the map, it ceased to exist. In a couple of weeks. That's insane. The Soviet Juggernaut was coming and Allies or no Allies the Germans weren't stopping it.