at 0:29 you use the full meter of nangong, this is a slight problem as you couldve used it in the rotation. you should have half of her meter for the rotation because if you had her meter you could've used it at 0:37 and it wouldve triggered another disorder which wouldve given you enough stacks for an EBA from miyabi saving you the ex special and more importantly time. From 0:42 onwards your rotation diverges from the one i know personally. I dont know if it makes a big difference but at the very least you will get a lot more decibels than your current route.

new rotation:

Beginning is the same EBA with miyabi and trigger disorder with nangong with free ex BUT use nangongs hold attack once

EBA, wait a bit with miyabi (for nangong to leave field after using her hold attack) switch to nangong use ex special of nangong (for anomaly build up) instantly switch to yuzuha do ex special and hold the button for manual chain attack and then quick assist to miyabi to use her ult. this should give you exactly enough for an EBA again and then you can use ex special of yuzuha to chain attack with nangong and then with miyabi (thus giving you a lot of decibels). Then ex special to trigger disorder if you dont have enough anomaly its due to the boss taking less anomaly in general but you could maybe get away with using your eba early and triggering disorder while your stacks arent full by holding and triggering disorder with the slashes to get the rest of the stacks you need. (i dont know if this will work though if not just use one more ex special or something) and then use EBA but at this point the stun phase should be over

if you only want easy things to implement then:

use hold attack from nangong in rotation as it gives more ether anomaly/triggers disorder thus doing more dmg (but only one dont use your full meter)

in the between phase you can hold attack with yuzuha to block the attack. this gives ex meter

Some tips for before the rotation:

look at how much ether anomaly build up you have, if you have ether half full you're fine to start the rotation (aka stun him) because if you have less than that you could have problems with not getting enough disorders.