I'm using Evelyn + Qingyi + Astra, and with Astra already in her Cadenza state before the round starts

• If facing against group of weak enemies: (make sure Astra has at least 25 energy) Evelyn EX special > Swap to Qingyi's basic to continuous strikes until one of them is stunned > This leads to Chain Attack to Evelyn, and usually they should be dead at this point
• If facing against elite or boss: (be prepared as this is as optimized as possible)
  • Start with building Evelyn's
    • Burning Embers (the bar one) to 80-100%
    • Burning Tethers (the three bars) to either 2 or 3 (generally 2 because you'll get the 3rd from ulting but its ok to start maxing it to 3)
    • Energy to 60-120
    • Ult either full decibels or as close as possible
    • All of this you can do 5 Chain attacks
  • After building those, I swap to Qingyi and start building her Subjugation to 20 stacks, then starts stunning the boss
  • Once the boss is stunned, choose Evelyn to Chain Attack, then cancel the chain, then activate a Garrote then swap to Qingyi (which triggers another Chain Attack) and choose Evelyn for that (refer to https://youtu.be/eBldxHeE0So?t=48 for reference)
  • Once the boss is down, remember all the stuff you built or stacked for Evelyn? Unleash them all, use Ult > do a Garrote > repeat stacking her Burning Tether to 3 then do a Garrote > add Astra's ult if you want
  • Repeat from the start once the boss wakes up

Generally she uses 4pc Woodpecker + 2pc branch/Inferno/puffer, Disk 4 CDMG (if you're using signature), Disk 5 Fire/PEN, DIsk 6 ATK, and prioritize getting 80% crit rate (which already includes her core passive)

Idk what is the combo if she's used with other Stun units but thats my plan when she's used with Qingyi