Just want to know, how does your build and methods apply to 90% of the majority who don't have your type of promotions?
Melee Anti Despair Demon tactics are demonstrated. General Mobbing techniques are demonstrated in the video.
More specifically for the Dragon battle itself:
Shield Wall against the Dragon's attacks & attack patterns here. Watch for the tells she does, and shield wall those attacks, then counter with your own attacks. Your attacks will help replenish your Stamina in between her attacks. My build includes Stamina regeneration passive Deep Reserves.
Learn to target her legs specifically, relative to your position, and jump to their position using forward jab and shield bash.
Learn to Shield Wall / Attack Cancel as I do, holding down movement forward for the lightning fast jab attack to cover the gap distance
Use Shield Bash against the Dragon's Guard
Always position yourself with the enemy to your front, use cover & terrain to your advantage. I use trebuchets and castle walls as cover as Dragonlings approach and the Dragon does her Wing Flap.
Shield Wall can block her wing flap damage.
Watch how I prep trebuchets, using 7.5 turns exactly, so I only need half a turn to actually activate the Trebuchet when I need it.
Learn to run and circle strafe enemies, dodging their ranged attacks as you approach them or run away from them (toward trebs).
Bring the appropriate resist pot to your Dragon Battle.
Drink Mighty offense for a boost vs enemy guard, to help take it down faster.
Shield Bash (upgraded) + Guard Smasher passive both enable you to smash down enemy guard, leading to 20k+ damage vs the Dragon's guard.
You can do all these things, and play a lot more effectively without relation to gear & promotes. This is just off the top of my head. I'm sure I'm missing things to the observant audience.