Breath of Hope definitely has a problem with excessive spawning of enemies. They also ALL have powerful shotguns in a close quarters map. I hate this mission.
That said, your video shows only you, Warm Hans (possibly the worst gun for killing spawns) alone against the horde. A full party would be doing better, and if there was a Kuzmann there, they would have been toasted very quickly in that choke point.
Not to downplay your complaint, because this mission is one of the worst when it comes to spawns, but a single raider with the worst gun and no party to support is the worst-case scenario and makes sense that you got overrun.
