I prefer The Motion Picture to TWOK so there you go it’s a subjective thing to a degree but I think there are measurable qualities to the first two Star Wars film that dip afterwards.
Certainly there are, especially when you get to the prequels, but I think the reaction to Jedi tends to get unduly drastic when it’s folded in with them. When you’re looking at the whole thing as a continuous chain, yes, Jedi was where the quality first declined and after that every movie was a step down. But if you take the prequels out of the equation for a second, it stops looking like the sky is falling. The first two movies are great. The third one loses some of that mojo, but it’s able to coast by because we’re all invested in the characters enough from the previous films that we keep watching, and really the movie’s enjoyable enough and it’s got some inspired set pieces. End of part one. Part two: twenty years later, George Lucas makes some more movies and they’re just awful and it’s obvious now that his approach is wrongheaded and he has terrible instincts and he was only ever as good as the people he surrounded himself with and he’s maybe a little nuts. That’s all a bummer, but it’s kind of extraneous. It really only affects part one if you let it, especially because that part two is over by now as well. 1997-2012 were indeed the dark times, and 1983 foreshadowed it, but I think it’s hyperbole to actually say it’s all the same thing.
EDIT: uuuugh I hit “quote” instead of “edit” and made a mess of things. Apologies.