How Was Cad Bane So Good At Defeating Jedi?

Bane treated Jedi as a speciality rather than a hazard. Where other hunters priced Force users as not worth the risk, he took the contracts nobody else wanted and built a loadout aimed squarely at Jedi weaknesses: rocket boots to match their speed, breathing tubes that made a Force choke pointless, gas and flamethrowers. Preparation, not luck. (The Clone Wars, "Hostage Crisis", "Holocron Heist")

He chose the fight#

The sensible rule for a bounty hunter is to leave Jedi alone. A Force user can see your shot coming, close distance faster than you can back up, and take your weapon out of your hands without touching it. The risk-to-payout maths does not work. (Attack of the Clones; Star Wars: The Clone Wars)

Cad Bane ran the opposite policy. He actively took jobs where Jedi were either the target or overwhelmingly likely to turn up, and he did it often enough to build a reputation on it. The record is direct about it: Bane specialised in fighting Jedi and dueled some of the most skilled Jedi of the Clone Wars, including Obi-Wan Kenobi and Anakin Skywalker. (The Clone Wars, "Hostage Crisis", "Holocron Heist", "Hunt for Ziro")

That reputation is why Darth Sidious kept coming back to him. Bane was hired repeatedly by the Sith Lord for jobs that needed someone who could operate around Force users, including infiltrating the Jedi Temple itself to steal a kyber memory crystal listing Force-sensitive children across the galaxy, and later abducting those children. If you need a job done inside the Jedi Order's own house, you do not hire someone who is scared of Jedi. (The Clone Wars, "Holocron Heist", "Cargo of Doom", "Children of the Force")

The Fett inheritance#

Bane's timing helped. After Jango Fett was killed at the Battle of Geonosis in 22 BBY, Bane was considered the best and one of the most experienced bounty hunters of the era, stepping into a gap at the very top of the profession. (Attack of the Clones; Ultimate Star Wars)

The inheritance was more than reputational. Early in his career Bane was briefly mentored by Jango, who carried the gear of a Mandalorian culture that had fought the Jedi in old wars. Bane's contribution was to strip that thinking out of its cultural context and apply it as pure engineering. (Star Wars Helmet Collection 41; Age of Republic: Jango Fett 1; The Clone Wars, "The Mandalore Plot")

He passed the same approach on. Bane trained the young Boba Fett, which closes the loop rather neatly, since it was Boba who eventually put a blade through his chest in the streets of Mos Espa decades later. (Star Wars Helmet Collection 41; The Book of Boba Fett, "Chapter 7: In the Name of Honor")

The kit#

The gear list is where the answer really lives, because every piece of it addresses a specific Force ability. (The Clone Wars, "Hostage Crisis")

Rocket boots handled the speed problem. A Jedi accelerated by the Force can cover ground faster than any unaugmented body, so Bane bought the ability to close or break distance whenever he needed it rather than trying to win a footrace he was always going to lose. (The Clone Wars, "Hostage Crisis", "Holocron Heist")

The breathing tubes are the clever one. Bane's cybernetics included removable breathing tubes running into his skull alongside a metal headplate, and their function was blunt: they let him survive a Force choke. Crushing a Duros' windpipe means nothing if he is not breathing through it. Every Sith and Jedi reflex that starts with lifting an enemy by the throat simply stops working, and the enemy gets a free shot while you find that out. (The Clone Wars, "Hostage Crisis")

On top of that sat the rest of the arsenal. Dual LL-30 blasters, flamethrowers, knockout gas, a wrist comm to coordinate, and the wide-brimmed hat he was never seen without. He also flew well enough to matter, running a modified Rogue-class Porax-38 called the Xanadu Blood that he bought with Sidious' money. (The Clone Wars, "Hostage Crisis", "Holocron Heist")

What it bought him#

The results speak for the method. On Teth, hunting the missing Ziro the Hutt, Bane found himself facing Kenobi and Quinlan Vos at the same time, held his own against both using a rotating mix of weapons, and got away. Count Dooku later put him through the Box, a gauntlet built to kill, and Bane came out of it alive and in charge of the plot to kidnap the Supreme Chancellor. (The Clone Wars, "Hunt for Ziro", "The Box", "Crisis on Naboo")

He was still going under the Empire, taking a contract from Kaminoan Prime Minister Lama Su to recover the clone Omega, and he was still going in the New Republic era as an enforcer for the Pyke Syndicate on Tatooine. A career that long, in that line of work, is not survivable by reflexes alone. (The Bad Batch, "Bounty Lost"; The Book of Boba Fett, "Chapter 6: From the Desert Comes a Stranger", "Chapter 7: In the Name of Honor")

Bane's own view of the Jedi shifted over the years. Early encounters left him believing they always offered a fair fight. As the war ground on he decided the Order had changed and no longer did. Coming from a man who built his entire career on making sure fights were never fair, that is a fairly bleak assessment of what the Clone Wars did to the Jedi. (The Clone Wars: Stories of Light and Dark, "Bane's Story")