I have been a "Godfather fan" since I saw the first movie (then the second) (in the 70's) and later bought "Godfather: The Epic" on VHS.
That combined I and II in chronological order plus over an hour of extra footage omitted in the Theater release edit of I and II. I watched the epic a million times

And I read the book by Mario Puzo.. and a couple of his other books... helped fill in some details.
Godfather III a little disappointing... but I am not as down on it as many critics (still a great movie IMO)... I was most disappointed in the character of Michael... he had "lost his edge" (killer but justified) and to me did not even look the same as the younger Michael, despite being played by Al Pacino in all 3 movies.
I did also watch the Trilogy online (and posted some links).
As far as the "Reunion" links I posted above... I could not get through watching it all... all the actors (except Duval?) SPOIL the memory of the characters as they were portrayed 45 years prior... James Caan is a buffoon these days..... as is De Niro (daft Never-trumper leftist

Al Pacino is OKish.... but he had a quantum change after his early movies (GF 1 and 2, Serpico, Dog Day afternoon)... that is why I could not get into him in GF 3
Francis Ford Coppola did not come across great either... but I can make allowances.