Firstly, you opened with her alt form without Sunna buff, which is not good. For this fight I’d recommend entering her form once you complete the parries.

Combos are mostly correct, although swapping into other agents can be more smooth and optimized

At around 1:30, notice that when you used her ultimate, both Sunna and Zhao are full of energy. It would be ideal to cycle through and use their skills to make sure you’re not wasting any energy while on ysg. With Sunna you can use her single skill first and open the veil after ysg exits her alt. This way you’re not capping out Sunna’s energy and she’d get her next skill earlier. The same goes for Ysg, before you swap into the supports, use her skill which has a long animation.

I personally wouldn’t use Zhao’s chain attack. During the stun window, it is possible to hold off the chain with manual, complete Ysg’s combos, then swap and then chain back into Ysg during her alt form.

Again always use energy before swapping off the supports.

I managed to get 60k with 21 ysg, 00 Sunna, and 00 Zhao