No Russian involvement.
Castro used Oswald with the help of Cuban-Americans.
There was a growing group of operatives that wanted to see him gone.
In one of many documentaries I have viewed on this subject, it was noted that there is a very easy, simple way to determine whether the gov’t was behind any “event”:
Right before it occurs, security is withdrawn in some manner: ex. The recording cameras mysteriously not “on” when Princess Diana was murdered.
In the case of JFK, note that seconds before he is shot, one Secret Service agent is called away by his fellow agents in the car behind the President’s car, from his assigned role. Note that he shrugs his shoulders in bewilderment, but does comply with their request that he leave the President’s car and join them behind it.
IIRC, it may have been Jim Marr that revealed that this particular agent was specifically assigned to protect First Lady Jackie. It is reasoned that because he was not protecting the President, he was not “in the loop” of knowing what was about to happen, and thus, his bewilderment and shoulder shrugging.
AFAIK, no other explanation has been suggested to explain this removal of security seconds before the “event”.
It seems likely Global Elites staged that successful coup and have been firmly entrenched ever since.