Stalin would have happily supplied the Germans as long as they kept their focus on the UK. The longer those 2 would tire each other out, the better it would have been for the USSR.
I doubt that. It's not as if the USSR did not need what Germany should have paid with. Stalin's rearmament plans, which are not a luxury for the USSR at this time, rely heavily on German tech, know-how, finished goods - which the Germans are not sending along.
On this same tit-for-tat issue, one can look up the story of the Soviet supplies to the Spanish Republic. Did they send those to counter Fascism? - yeah, but add that the USSR pocketed the Spanish gold reserve.
But the clincher is an analysis of the Soviet supply flow from the winter of 1939 to June 1941. The first big trade deal was already operational soon after the fall of Poland. Yet the Soviets sent only a meager trickle of what they had promised, throughout that winter and spring. Now, Germany was surely focused West at this time, yet Stalin did his very best not to help the Germans.
Then, once the Germans were triumphant in the West, the Soviet taps opened up. Stalin was essentially paying "protection" to the racketeer, up to the end of June 1941. The more the German focus moved East, the more Stalin sent - receiving nothing.
The above, IMHO, is evidence that while the Western capitalist states and Nazi Germany were all enemies to Stalin, he thought that some enemies were more dangerous and worse than others, and he had a preference about who should win.