By default, private network mode uses an external server. Sometimes you have to approach the episode several times because it is difficult (we play on level 3 of difficulty 5 - at the beginning I recommend playing on level 1, even if you have already played some FPS), but thanks to the randomness, each episode can surprise you every time. And what's really cool is the lot of randomness in the game. Incredibly huge hordes of zombies to kill. Each act is divided into several episodes. Bots can be disabled in private network mode. So far I'm only playing the campaign, with one friend + two bots. This game rocks and I want to come back to it all the time.
Recently I had so much fun playing Dead By Daylight about 2 years ago. It's been a long time since I had so much fun playing a game.