How to ensure a single player run will happen?
On ps4 you can just turn off your internet connection if you don't stream the game then you are sure to be alone. If you are streaming it and you have no capture card then there is no way.
But seems you are on pc you can just turn off the internet connection or even do it on the settings of the game i think (i don't have it on pc so i don't know the exact menus).
Oreo321 이것을 좋아함
For PC (Steam) if you go top left and click steam, select steam offline: This will make sure you are only singleplayer. (If you need help with this look up tutorial online) For Epic (I dont have epic) you can turn off your firewall
Oreo321 이것을 좋아함
for epic you also could try offlining the launcher. for steam without going offline you could use any emulator