Lend Lease wasn't just an ungodly amount of military equipment, a significant portion of which later ended up in the hands of the ChiComs in Manchuria, it was basic everyday necessities and industrial goods. Americans were made to deprive themselves of butter in favor of margarine in order to keep the Red Army fed and the Soviet's remaining industry running. You quibble over whether or not Moscow would have been won without Lend Lease, but the Soviet War effort would have absolutely collapsed without FDR bleeding America to keep the Soviets fighting just out of sheer lack of foodstuffs and machine tools.
Lend-Lease trucks, locomotives, foodstuffs, fuel etc were absolutely decisive to keeping the Red Army fed and moving through the latter half of the war, and therefore enabling them to take the offensive in the way they did. As were other, less glamorous but nonetheless vital things, like the explosives needed to make shells - 1/3 of all explosives used by the USSR were either provided through LL directly, or produced with precursor materials provided through Lend-Lease.
Most optimistically, without Lend-Lease, absolutely none of the grand offensives of 1944-45 happen. There will simply not be the shells, the vehicles, or the fuel to pull it off. The Soviets might bleed themselves white grinding forward anyway, putting even more of the fighting on men instead of using firepower, and probably meet the Western Allies somewhere in Poland.
Much less generously, without LL, the Red Army by late 1943 going into 1944 is going to be starving, immobilized, and running out of ammunition. Then it's shortly going to stop existing as a meaningfully coherent fighting force, while the Germans run rampant. Maybe they keep the Army fighting by shorting the homefront even more, and stay in the fight at cost of an actual massive famine for the civilian population, and hold on by their fingernails, at an even more tremendous human cost than already happened.
Who knows.
These counterfactuals are fairly impossible to verify, because a change in circumstances is going to make for different decisionmaking, and that's essentially impossible to predict.
In any case, the Germans are still going to lose because if nothing else, by 1946 the Anglo-Americans are going to come along advancing behind a curtain of nuclear fire, but Lend-Lease very much was the deciding factor between the Red Army ending the war in Berlin, and the battered remnants of the Red Army being met by the Western Allies on the Vistula in 1947 or something.
“Dem Chanks can only steal frum da hu-whuite man!”
