So I have been playing BO4 Custom Games Zombies Mode and here is what I think about it. I know I am late to this but here it is. To do it you have to be in the lobby and select custom. When you do this you can add some things to it here are somethings you can add.
There are way more but here are some for an example. When your in the game anything you added will be in the game. Say you put on 5,000 points you will spawn with 5,000 points.