I haven't seen any videos on a melee method for this echo boss so I decided to make one for whoever might be struggling due to picking melee masteries.
Enter the cave
Do 2-3 attacks
First set of tiles
Do 2-3 attacks
Second set of tiles
Do 2-3 attacks
Third set of tiles
Do 2-3 attacks
Fourth Set of tiles
Do 1 attack while it's charging it's special attack
Switch to secondary attack style and hit it once while running to the wall before it launches it's attack.
Rinse and repeat.
I unlocked all melee masteries so your attack speed may vary if you don't have the last couple masteries.
Enjoy!