Base strategy was took from Eckogen and reworked to be stable/easy (for people who struggled like me).
Units are quite replaceble in this team. You don't need any specific healer, just bring the best ones you have. Nealter-can be replaced with Kal'sit (so you can replace one healer with another dps). Surtr can be replaced with Texalter/Irene/etc. Eyja can use skill 2 too OR you can switch her with another caster (gonna be longer). Second tank can be whatever, it is needed for task and artillery in 3d phase. Only irreplaceble parts are Thorns and Hoshi (probably replaceble with Nian) with highest lvl possible (90lvl in my case).
1st wave:
Operators placed near towers are needed just to capture said towers, so they can just chill. Towers captured = retreat operators.
2nd wave:
Be sure you have enough DP to place your tank when you place your healers. Also, catch boss so it is positioned on the left side of the tile (so your Nealter/Monster can dps). If you use Nealter - activate her skill as on video, otherwise (if you are late) - keep it for next mob wave (so mob + bomb wont kill Nealter).
Be sure to retreat operators when boss is on low hp to stall for cds.
3d wave:
Just be sure artillery doesn't target and kill Thorns while you setup operators. Play safe here.