No way around it - someone has to stay behind so everyone else can escape. Who should hold the gap?
the artificer, backed by invented weapons and an army of constructs
the barbarian, with brute strength and stamina to the death
the bard, living up to the rep they built for themselves
the cleric, directly empowered by their deity to a final form
the druid, shapeshifted to a massive creature backed up with beast army
the fighter, using combat tactics to duel multiple opponents at once
the monk, calmly and deftly dodging between enemy strikes to land their own
the paladin, channeling their noble oath into an implacable last stand
the ranger, sniping as fast as they can before switching to close combat
the rogue, assisted by traps of their own design
the sorcerer or wizard, burning their strongest and riskiest destructive spells
the warlock, directly channeling their patron's full powers