The Eternals, according to Chloé Zhao's movie, are a group of ten super-powered beings who were sent to Earth around 5000 BC to defend the planet against "the Deviants" - and nothing but, so they didn't help fight Thanos (yup, this is Marvel). We see bits and pieces of their long history on Earth, and their reunion in the present. And we see how they bicker.
This is a long movie, but I can give you a short review: ten main characters - plus the god-like Celestial who sent them, and the Deviants as their enemy, and one boyfriend whose name says he's going to be another superhero - is way too many main characters. It's pretty, but too bloated and there's still not enough time to get to know any of the characters. Think of "The Avengers," one of Marvel's most successful movies: six heroes, four of whom (Iron Man, Captain America, Thor, Hulk) had already been introduced in their own movies, and a lead enemy (Loki) who had been introduced in one of those other movies (Thor). We knew the characters already. Every single character in "Eternals" is new, and there's twice as many of them as in "The Avengers."
Did I mention that they bicker? We're supposed to see them as a family, with all the tensions and disagreements of 7000 years of living together - which may be why they've been apart the last 500 years. But when they get together again, it all comes back. Several of the characters are quite annoying - this appears to have been an attempt to make the cast of too many characters distinct from each other, but mostly it makes you not care about them.
I've been thinking about other movies with a large number of main characters, and a very successful one (and a personal favourite) that came to mind was "Ocean's Eleven." How did it succeed in introducing eleven new main characters - plus the bad guy and the girlfriend? That's easy: it was okay with some characters being caricatures. Remember the acrobat guy? He's got maybe two speaking lines. And Saul - he's basically "weird accents and heart attack waiting to happen." Or the brothers - they're just a running gag. The movie concentrated on George Clooney's "Danny Ocean," Brad Pitt's "Rusty Ryan," and - to a lesser extent - on Julia Roberts and Matt Damon. "Eternals" wasn't willing to cut those corners for itself ... so it happened anyway, in a much more messy fashion.
And then there's the accents thing. When they arrive on Earth, they all speak modern English. One of them has a strong Irish accent ("Druig"/Barry Keoghan), one has a strong Scottish accent ("Ikaris"/Richard Madden), and one has a Hispanic accent ("Ajak"/Salma Hayek). And 7000 years later, they all still have the exact same accents. This seems ... improbable. It's a small thing compared to the film's other problems, but I found it annoying.