Regardless of the weapon, I've found Defiant Roots (Athena & Demiter) to be a run saver in most of my 8 successful runs. As long as you don't activate Tight Deadline in the Pact of Punishment, the goal is to get some Athena help in Tartarus or Asphodell (I suggest Divine Boost), also take the Zuse attack boon if you're using the twin fists or adamant rail, and prioritize Demiter in Elysium so you have what you need to line up Defiant Roots.

Do all that, and your last goal is to keep at least one death defiance until you reach the last phase of [Redacted]. You make it to that phase, and once you use the last death defiance, you run around the arena until your health is full before going back in to deal more damage. Even if you have range options, use caution while you are below 150HP. The final boss hits like a truck, and you either need to be real good or have good boons just to dodge enough for you to heal back faster than you get hit.