I’m not going to disagree with the view that taking on Russia would have ended in tears, however the issue about tanks is not as clear cuts as it appears.
By this stage of the war, the Russians had decided not to re-equip their tank units with better designs - production was what it was all about - and to them it did not make sense to divert resources into stronger tanks.
Russian tanks were becomong outdated, the Panther had reliability problems but was better in battle than anything the Russians had, there were too few of them.
The King Tiger again was too few and not reliable, but was more than a match, and the Elefant was not mobile enough, however it too was more than a match for Russian tanks.
Thats the German tanks, but in the meantime, the allies had developed the Comet and Firefly, and were literally only months away from putting the Centurian into service when the war ended.
The firefly was able to take on the German tanks, and would certainly have been capable of dealing with all but the Russian IS2.
The Comet was very closely related to the Centurian, so close that you could consider them simply differant models of the same thing.
The Centurion went on to dominate tank battles right through to the Arab-Israeli conflict of 1973 - albeit with upgrades to the gun and fire control.
In other words this tank was probably the most effective tank for around 20 years, and that includes dealing with all the cold war Russian tanks.
Not enough of these available?, well you have to consider that in 1945 an order for 800 of them was placed, and this was for the modified up-armoured MkII version. The MarkIII followed not long after with its stabilised and significantly more powerful gun.
This is all by way of saying that Russian tanks by 1945 were not all that, they would have been seriously outgunned and outclassed, and nothing that Russia produced in the decade after the war would have been capable of challenging that.
When you start to look at air power, the differance is just as big, by than the Allies were bringing jets into service, the Russians did not have a heavy bomber capable of taking the war to the Axis, and their fighters were heavily outclassed by both British, but especially US aircraft.
Throw in a few nukes, takes away the previous material support of Russia by the US and things stack up more closely than it might first appear.
Lots more blood, on both sides, mostly Russian, but still the logistics would have eventually worked in their favour.