While undoubtedly true, one should keep in mind that Stalin first cynically entered into a non-aggression pact with the nazi regime, showing blatant disregard for Poland in the process.
Not to mention that a significant part of the Soviet Union's losses in WW2 came about from a similar disregard for the lives of its own soldiers.
This is not to discount the sacrifice made by those who fought and died, though.
(And Treptower Park is, as you say, hauntingly powerful. I've been there on three occasions when visiting Berlin.)
That was 80 years ago and since then the Soviet Communist regime killed more people than Hitler. Their "good deeds" are becoming thinner and thinner.
Remember the USSR was allies with the Nazis and only turned on them because they were betrayed.
Spending your citizens lives cheaply is not a noble thing.
The US had nukes and its manufacturing and soldier population was massive. Coupled with the Western allies Germany was going to lose once America entered the war (see Churchill’s memoirs). USSR did accelerate it though.
The red army took Berlin and ended the Nazis. It was an Allied victory but it came about because Russia put their full might into stopping Hitler.
This is not insignificant if you don't like what the third reich was up to.
It came at a tremendous cost to mother Russia, 20M of her sons died in the process.
I encourage you to visit the war memorial in Treptower Park. It is built out of the red marble stripped from Hitler's Reichschancellery, and it is a hauntingly powerful place.