I saw the original trilogy and the prequels around the same time. I was maybe 10-12 at the time, so it's not like I have childhood nostalgia for one and a hyper-critical lens for the others.
I didn't mind Phantom Menace too much, the last fight sequence made up for a meandering movie, found AOTC ok but very forgettable, and *hated* ROTS, had a strong urge to walk out. The endless meaningless comic-book fight of Anakin and Obi-Wan, the ending with the NOooooooooo, and freezing the characters in place for 20 years - ruined my mood.
I loved the 3 original movies equally, I know adult reviewers find 6 bad, but as a kid I loved it all.
I don't think it's just nostalgia vs heightened expectations, I think the originals were genuinely better movies.
Actually regarding the Original Trilogy, Return of the Jedi has grown a lot with adults over the years, which is good because, nickpicking aside (Boba dies, Ewoks) it's actually a very good movie.
Phantom Menace has actually been the movie that has grown on many as they have gotten older and they appreciate the story more.
Attack of the Clones well, i'm not sure if that will ever really grow on anyone as a whole, but it moves the story on.
Revenge of the Sith is a good movie, but consider that it was originally 4 half hours long ( just as Phantom was also) they could have maybe worked it a little better.
These three films are where Lucas had free reign over and no one pulling him back in as was the case with the original trilogy, which helped make them where they needed to go,
And aside from the The Force Awakens, the other two were just not great as a result of Disney having zero plans thought out and well JJ wasn't bothered as it was only one film he was initially responsible for and that set up was ignored by the director and writer of The Last Jedi and JJ was then begged to come and fix it for The Rise of Skywalker which was by then far too late.
Thankfully Dave Filoni & John Favreau are saving the franchise at this point with the animated work and the Tv Series with more of that to come from our studios also (Anime Star Wars Soon)