So, from 1:22 - 1:32, the boss just sat there tanking hits. There were other long sequences where the boss did nothing like that as well. And this is supposed to be hard mode? Or is that an AI glitch?
At the part you mention take a closer look and you’ll see I depleted the boss’s shield, leading him to get staggered for a while and I am following it up with Beta abilities which are also staggering him. Whenever you use Burst or Beta abilities, any enemy gets a knockback plus stagger. As for tachy mode that used for a bit against him, every attack in tachy mode is a stagger. The only attack he does and he stays in one place, is the attack with these golden energy balls. The moment these balls disappear, he directly attacks.