... which is essentially a miniature version of Maul's iconic, glaringly show-offy double-bladed lightsaber.
Plus, those who obsessively scoured Vos' office looking for clues that Ron Howard faked the moon landing or something might have noticed that Vos has a Sith Holocron on display -- a reference to Maul's Rebels storyline.
Even more pointedly, Han's Crimson-Dawn-employed ex Qi'ra casually mentions that she's been trained in "Teras Kasi" -- which indoor kids likely recognized as a reference to the martial art invented for that Star Wars fighting game which finally allowed Luke and Chewie to act on years of unspoken hatred.
After fans theorized that Darth Maul's acrobatics may have been Teras Kasi in action, the novel Darth Maul: Shadow Hunter made it official, with the author specifically mentioning that Maul fought using Teras Kasi. Solo's screenwriters even admitted that the Teras Kasi detail was a "nugget" meant to hint at Qi'ra's connection to Maul. So your mom's insistence that you didn't spend your entire teenage years playing abysmal PlayStation games and reading Star Wars message boards ruined your chances at predicting a cool twist. Thanks a lot, mom.