Seen a lot of great tips but I want to add the below as it took me nearly a week to figure out new mechanics.

T3-F3-Enoch-F4x2-F3-B3-B4x2

Keeping enochian alive for 30 seconds gets you poly, haven't got that far because mobs die by first B4 of the above rotation.

Breaking it down

F3-F4x2-F3: F3 grants access to F4, only enough time for two, casting F3 resets the time, can't cast another F4 or enochian drops so cast B3 granting. Access to B4. Same concept as fire phase, cast 2 B4, reset timer with B3 and rinse and repeat F3-F4x2-F3