Not a conspiracy in the more surreptitious sense that most people consider. It would bear all the same hallmarks though, and I guess that’s what sets off people’s radars
There may be forensics technicalities that are hard to explain but it seems that in any event that is highly ‘investigated’ people find too many patterns in the noise (9/11 for example)
Like most of those Cold War events, these cover ups look more like protecting intelligence sources and blunders than some large overarching cabal
The official explanation for 9/11 is also the simplest possible explanation: terrorists carried out a very low tech and plausible hijacking attack that exploited some rather obvious holes in our airline security.
The 9/11 conspiracy theories are orders of magnitude more complex than this official narrative.
I don't think the JFK "second gunman" theory is more complex than the official truth. In it's simplest form (Oswald worked with another gunman, but there was no overarching conspiracy involving Russia or Martians or lizardmen or whatever pulling the strings) I would argue it's simpler than the official narrative.
As I said elsewhere, the only evidence of a second gunman is we know Oswald was a good shot with a gun and so needing 3 shots (with a scoped rifle at close range - less than 100 meters) is something to question. But in the end it seems more likely he would have pulled the trigger himself and thus not needed help.
But I agree with you: I cannot imagine that the Soviet government wanted war either. There is no way that a plot to assassinate JFK would have come "from the top" of the USSR.
There is definitely a middle ground sort of answer, where Oswald was involved with the USSR but they truly had no idea he was going to shoot JFK. That seems completely possible.
Of course, the Soviet government was enormous and not monolithic. There's no way Khrushchev or the government as a whole wanted open war with the USSR, but maybe some did, and maybe some thought that they could prod Oswald into an assassination without getting caught. Certainly, the USA and USSR engaged in some extremely high level brinksmanship in those days: the Cuban Missile Crisis, U-2 flights over the USSR, etc etc etc.
Do I think any of that is likely?
I don't even have a guess there.
Those scenarios seem entirely possible to me! But I have no idea of the likelihood is 0.0000000001% or 99%! I certainly think there are simpler scenarios for sure, like Oswald simply working in tandem with a second rando guy who had a rifle and wanted JFK dead.
The only thing I'm really sure of is that it was in the US government's best interests to sell the idea that Oswald was a lone crazy guy and that there wasn't some looming existential threat to America from the USSR, the mafia, Martians, or whomever. Any one of those things would have shaken America to its core, wrecked our international prestige, and probably lead to war.