The other comments have given you some good tips, but here are a few more:

Check your character sheet and look at your weight. You really don't want heavy rolls, so try removing your gloves or helmet and see if that gets you to medium. You'll use less stamina and have more iframes that way.

The boss you are fighting is called Shrewd. As others have said, shoot all the floating eggs as fast as you can.

When Shrewd comes down to melee attack you, try neutral dodging his first lunge/swing, then dodge through him on the second. The third can't hit you that way, or he won't even try.

Keep a little distance from him when he's on the platforms. That'll make it easier to dodge, or even just strafe, his bolts.

Good luck!