I had that same conversation with someone years ago about Indiana Jones. They grew up with a six hour film, just as you’re pointing out with Star Wars.
You had the same conversation with me right after TFA came out too, and made reference to this same ur-conversation about Indiana Jones 😃
Anyway, the childishness of ROTJ has never really bothered me the way it does a lot of people here. I think it’s fine that there’s a “the goofy one” in this franchise. Look at Planet of the Apes. Those are all over the place in tone, and no one’s angry about them. I’ll admit that it’s not the most dignified ending for the saga, but that’s since become a non-issue.