Managed to optimize my squad for this level because I realized I can remove my low-level Provence and still win.

Because enemies has increased ASPD, your melee operators will get stunned quick by enemy Snipers, so it is recommended to not deploy many melee operators and use Snipers for this stage.

Mayer provides a very cheap bait against enemy Snipers. The summons have 1 block, so Agents will only hit it once and then move past it. If the summon is in low health, you can use Mayer's S2 and redeploy the summon, so it is very useful. The alternative is high-health 1 block operators such as Melantha.

A slow supporter is used to ensure enough damage is dealt to some enemies that bypass the middle route. Alternatives are any high-DPS ranged operators.