Did FDR yielded too much to Stalin in terms of Eastern Europe and thus help to make USSR a superpower?

indirectly?

lmao!

At the Allied summit meetings, FDR had a constant view that Stalin supported his democratic hopes for the world afterwords. FDR also kept his attention on the immediate needs and issues, leaving the future of Europe for Churchill to worry about, and then ignored Churchill's fears of Soviet ambitions.

All that said, the future of Eastern Europe was left to the pace of the advances by the Allied forces. The Red Army overran all the nations later held under Soviet influence, and its possession made other views irrelevant.

Stalin broke all his promises to the Allies about Soviet behavior post-victory, but he already had possession of what he was going to get out of the war.

In brutal terms, FDR and Churchill traded Eastern European lands and freedoms, plus large amounts of Russian blood and treasure, for empty promises AND avoiding horrible casualties for their own armies.