As a result of this difference, it’s plausible Lenin would have been much more reluctant to make a pact with the Nazis, meaning that WW2 would have started later, and the invasion of Poland wouldn’t be grounds for starting the war.

The Molotov-Ribbentropp pact was mostly a measure to buy time while Stalin moved the USSR's war-relevant industries eastward to protect them from a German invasion he fully anticipated (cf. Hitler being dumbfounded and terrified that his troops found railroad tracks in Russia that were not on any of their maps). I don't know how anti-semitic Stalin really was in his later years, there's some plausible doubt on the "doctor's plot", but even if we buy that, these weren't Stalins later years, these were the 1930s when it was absolutely clear what the nazi war machine was aimed at, which was the Soviet Union. Stalin had asked the UK and France about pre-emptively attacking Germany for a whole year, but the UK had declined. I doubt Lenin would have fared much better in persuading them, he was during his lifetime equally feared and reviled among the western powers. Would he have made the same desperate decision as Stalin? IDK, but he would have faced the same strategic challenges as Stalin and it's likely he would have come to similar conclusions.

That’s assuming the Nazis would have come to power in the first place, though, and that is questionable. Lenin was in favor of international revolution, whereas Stalin favored building socialism in one country.

There were plenty of attempts at a socialist revolution in Germany and some of them had direct backing from the USSR. Germany just had too many class collaborationists, too many reactionaries with too much backing from a revanchist ruling class that was not as absurdly incompetent as the Romanoffs, and the more radical workers weren't as tightly organized as the bolsheviks and actually jumped the gun on several attempted insurgencies. All of them happened while Lenin was still alive. As with the war preparations, Lenin would have faced the same conditions as Stalin and i don't see much reason to make different decisions, viewing Germany's socdems as the left wing of fascism like Stalin did wasn't a far-fetched conclusion after all the chauvinist, anti-communist, imperialist and class collaborationist crimes they had committed in the 1910s and 1920s. Lenin doesn't strike me as the man who'd keep repeating something that had failed over and over again.

Maybe the purges would've gone differently under him, i think Stalin did go overboard there, but purges in and of themselves were a neccessity in the early USSR, Lenin regularly had purges conducted to fight careerism, corruption and incompetence among the party ranks. Stalin was fed a lot of false intel about supposed coup attempts by German spies, and he unfortunately was very prone to fall for such red herrings, maybe Lenin would have been more careful and measured in that situation. Which would have led to the USSR and the Red Army in particular having more experienced personell to work with, which may actually have made a difference during WW2, bringing swifter victory at less Soviet casualties. That's possible. A lot of such small things are possible. But i don't think they would've tipped over to any significant alteration of history as we know it.