But them respawning borderline instantly and indefinitely makes breaking allies out a frustrating mess since allies cannot stealth for the life of them and fighting through all of that is absurd.
I think either a spawn cap limit, or some time before respawning makes more sense, and would be fairer gameplay wise. And if all of your bandits in a hideout are constantly dying, you'd probably give up on trying to reclaim it, at least until the people taking out all your bandits leave.
Boss floors already seem to have their own furniture and cells, couldn't allies just go there? Or have a location with zero enemy spawns specifically for the boss floors. Why is Fuuka fine with a massive bandit nest literally attached to her graveyard? Why are the bandits even willing to go there? What bandit chief thought it was a good location when it's directly attached to someone else's territory who could pretty easily forcefully evict you at a moment's notice?