Stupidity: When Han tells Drydon Vos that he and Tobias will steal unrefined coaxium from the mines on Kessel, Vos initially says no, as Crimson Dawn's relationship with the Empire would be at risk. Han then explains that the Empire wouldn't know they were working for Crimson Dawn. Vos then agrees but insists his top lieutenant Qi'ra accompany them, even though she is a known associate of Crimson Dawn and literally has their symbol branded on her wrist.
Stupidity: At the end Beckett had the opportunity to shoot everyone in the room but he chose not to.
Stupidity: When Enfys Nest reveals the atrocities committed by Crimson Dawn, Solo and Beckett are shaken enough to change their whole motivation and risk their lives in a gamble against the employer they had been terrified of so far. The information that Crimson Dawn doesn't follow humanitarian guidelines should have been perfectly obvious to both men all along. They knew they were working for criminals, and were mostly driven by fear, so Nest's story would change nothing for them.
Answer: Or they could've hitched a ride with the Cloud Riders.