3 player options for casual battles

A friend and I just got a 3rd friend to try TWW2 she had it on Epic when it was free but was reluctant to play even tho she’s really into wh fantasy.

We don’t want to play campaign mode yet, just one or two battles every gaming night before playing vermintide or other games she’s more comfortable with, but it seems three player games are not really implemented. Do we have any fun options for 3 players? What do you when you’re in a 3p night?