I’ll give you my suggestion, which is purely based off my childhood experience. I was 4 years old when TPM came out. Vaguely recall having it on VHS, but I also had SE 97 VHS. You know what movie I played the most? Return of the Jedi. Why? The third act, especially for the space battle. Then eventually AotC came out on DVD. You know what movie I replayed the most? AotC. Flashy and more colorful, to me at the time at least. And boy, once I got my hands on RotS, I played that on repeat so many time. Point I’m making is that, sure, introduce however you wish you to, establish the order (whether that’s release or chronological) but I’d highly encourage to let your kid freely choose which Episodes/Spin offs to watch over and over. Because honestly, trying to recapture that Vader/Luke twist these days will be rather difficult. There’s too many SW film’s now. So for a kid to invest their time into SW will make all the movies sorta run together in a blur. They will pick up on certain plot points, but it will most likely not land in the way people felt it way back in 1980, when there was only one SW movie to digest. At some point, for me at least, I never had that surprised moment of Vader revealing himself as Luke’s father. It’s like asking me when I learned what the color blue was. It’s simply integrated into my mind as commonplace knowledge. Even if you somehow managed to control the flow of when to show these movies are shown to your child, that doesn’t stop peers, the internet, and random strangers from spoiling it. That’s not to say it’s not impossible.
However, I think we’re missing the point of SW if we try to hard to have newcomers experience that shocking twist. I’ll tell you that instead SW overall had inspired me in so many ways. I drew countless drawings of the characters, the ships, and scenes. I made so many different objects from that universe with creativity. My imagination was fueled! I believe that’s more cherishible as a parent, to see your child have those imaginative gears running. They will not being able to fully comprenend the nuances of the story, but that’s totally normal, and will come with years under their belt. SW is supposed to evoke a sense of adventure and fun, and a child will fully absorb themselves into it way more than an adult. Then once they’re of adult age, they will be able to express the complaints you also have with the franchise 😂