What was the Soviet Union's response to growing German strength?relating to the international cooperation and confrontation 1919-1936
The Soviet Union's main response to growing German strength was to more or less make friends with Germany even though the Nazi ideology and racial ideas were completely anti-USSR.
Here are a few examples. First, the Soviet Union allowed the Germans to secretly train their armed forces (that they weren't supposed to have) in the Soviet Union. Second, the Soviet Union eventually signed a nonaggression pact with Germany in which the two countries agreed not to attack one another. Finally, the two countries had various trade agreements during the 1930s that were of some benefit to both countries.
So, even though Nazi ideas were very anti-USSR, the Soviets thought they were not strong enough to fight Germany and so they tried to be friendly.
Josef Stalin also wrongly assumed or believed that by making the Non-Aggression Pact with Hitler, there would be no chance of war between them. He pursued an aggressive purge of his own armed forces and killed most of his talented military officers, essentially leaving his armies leaderless on the battlefield once the invasion came.
When the invasion did happen, Stalin refused to believe he was under attack, refused to believe that he had been wrong, and locked himself in the Kremlin for five days and went on a vodka bender. Stalin reacted to growing German strength with diplomacy, therefore, and overconfidence that the diplomacy would keep the Soviet Union safe.