The surefire way of defeating Nine Sols Eigong(80%)

It's not hitless, nor no-damage, however, it is the most consistent and reproducible way to defeat the Eigong boss(80%) IMHO.
It focuses on the following goals:
Tweaking the game's input settings to avoid unintended game input.
Minimize chances of getting hurt due to the vulnerability frames.
Minimize chances of received Internal Damage turned into Permanent Damage.
Parry and dodge at the right attack blows and timings.
Maximize Internal Damage output.
Maximize talisman explosion output.
Exploit the seemingly unfair hitbox of a certain attack pattern to evade the attack and deal great damage to the opponent.
Maximize the opportunity to observe the enemy attacks' visual cues, to react accordingly.
Maximize the success rate to unleash the Unbounded Counter move.
Timestamps:
0:01 Checking status(Jades, Skills, Status)
0:14 Optimize controller input(unbind Azure Bow arrow switching buttons)
0:31 Preparation completed
0:48 Phase #1
1:58 Phase #2
3:19 Phase #3