"The glass onion puzzle box is really the only clue we need
Sometimes the answer to the mystery is right in front of you.

Editor's Note: The following contains Glass Onion: A Knives Out Mystery spoilers.
^ Rian Johnson's penchant for playing with the conventions of the mystery genre, as seen in Knockout and its sequel, The Glass Onion: Knockout Mystery. Neither Knives Out nor Glass Onion are traditional "whodunnit" structures, but instead double reveal stories within stories and turn to where the audience least expects it. Glass Onion goes a step further, directly hinting at the conclusion to its central mystery in its opening sequence.
Glass Onion is set in the early days of the COVID-19 pandemic, when billionaire Miles Brown (Edward Norton) invites his fellow "disruptors"—friends he made along the way to success—to Started Greek islands while vacationing in his private place. Among the invitees is famous detective Benoit Blanc (Daniel Craig). The only problem is that Bron never sends an invite to Blanc. Blanc quickly deduces that many of the invitees have real reasons for wanting Bron to be harmed, and soon he's drawn into another mystery.
In Glass Onion, Miles' Disruptor crew is a rather eclectic bunch. Claire Debella (Kathryn Hahn) is an ambitious politician. Lionel Toussaint (Leslie Odom Jr.) is a Distinguished Senior Scientist Miles' company Alpha. Birdie Jay (Kate Hudson) is a fashion designer/supermodel who just can't seem to stay out of the spotlight - for better or worse (mostly worse!) pretty much everything is wrong about the internet.
Everything About 'Glass Onion's Disruptors Is Revealed via Puzzle Boxes

More information about their personalities can be seen in the way they open Miles' box. Lionel is the only one who actually masters the puzzle and solves it with ease. It annoyed Duke that his mother was able to solve the mysteries. Claire is dismissive of her husband's attempts to help. Birdie, rather ignorant, lets her assistant Peg (Jessica Henwick) figure it out. This dynamic continues when they arrive on Miles' island, and the real reason behind their connection is revealed. Both Lionel and Claire are betting their reputations and careers on Miles' new energy source, Klear - and it does have explosive side effects. Duke relies on Miles to succeed as a man of influence, even as Miles imposes those moves on his girlfriend Whiskey (Madeleine Crane). When Birdie invested in sweatshop labor to create her line of sweatpants, she went too far— It also puts Peg at risk.
But these puzzles also reveal a damning truth about Miles' so-called "genius": he's not really a genius. Blanc even considers them a piece of cake! But it's not just that - Miles reveals he hired Phillip Glass to compose the "hole" that rings through his island every hour and Gillian Flynn to sing it for him Guest writes a murder mystery to solve the mystery. In short, he has no ideas of his own.
Miles Isn't the Genius He Claims To Be in 'Glass Onion'

Going even further: When Miles' business partner Andy Brand (Janelle Monae) objected to using Klear and tried to walk, Miles discredited her and sought out disruptors in the process s help. But when Andy finds evidence that the real reason for Miles' success is her and not Miles, he poisons her and takes the napkin containing her original sketch to Alpha. However, it never occurred to him to destroy the incriminating evidence until Lionel pointed it out. As Blanc puts it, "Miles Bron is an idiot."
Indeed, it was the simplicity of the case that led Blanc to err. detectives used to solve more An intricate and well-thought-out case proves Miles' stupidity is an obstacle. Again, Johnson foreshadows this in a clever (and rather hilarious) way. Blank spent most of his time in quarantine playing Among Us in the bathtub with his friends — including the late, great Angela Lansbury and Karim Abdul Jah Barr -- pointing out that he's doing a terrible job of it. Unlike Miles and Jammers, Blank has someone to tell him the truth, and he's a true genius!
Sometimes, the Answer Is (Stupidly) Simple

Blanc is also assisted by Andi's sister Helen (also played by Monae). Helen's way of handling things is simple and effective. While on the island, she manages to dress up as Andy and, thanks to a few hastily poured bottles of hard kombucha, uncover the truth behind the connection between the Disruptor and Miles. She also brings down Miles' empire by throwing samples of Klear into his fireplace - literally burning the glass onion.
But again, it's back to the beginning. Helen stared at the puzzle box for her sister, anger slowly brewing in her eyes. Finally, she leaves the screen...and returns with a hammer, breaking the box into pieces. It shows that sometimes the simple way is best.
Glass Onion: A Knives Out Mystery is currently streaming on Netflix.