m not going to credit anyone as there have been multiple people claiming foundership and I cba working out who is lying.

METHOD ONE

This lobby can get around 1k kills per game.

What you need

Two friends
Good co-ordination with those friends

Tutorial

Part 1 - IX Stack

Load up BO4
Load into Zombies
Back out
Click Multiplayer
Quickly move over and Spam A/X on the IX playlist above zombies
If done right you will get a lobby error and then will have IX as your playlist
Have your two friends join your game
Search for an IX match
Have you friends leave alone
You will all have IX playlist now
Part 2 - Bot lobby

Have friend 1 go into custom games
Join friend 1
Have friend 1 press B/Circle and hover over leave with party
You hover over options using DPAD (not the little white circle cursor thing)
Count down from 3 and on go, friend 1 backs out and you spam A/X on options
If done right you will have the custom game stack
Have friend 2 search for a game with the IX playlist
Also have friend 1 search for a game with the IX playlist
Wait a while (this can take some time) and you and friend 1 will match with friend 2
Have everyone leave the game except you (make sure they leave alone if asked)
Edit the gamemode + settings how you like
Have friends join back
Fill game with friends (or second xbox) DONT USE BOTS THEY SEEM TO CAUSE CRASHES
Game will start
GG
----------------------------------------------------------------------------

METHOD 2

This lobby could get 2-3k kills a game

What you need

5 Xbox/PS4
2 controllers for each
Netduma/Geofilter Router
Patience

Tutorial

Have console 1 invite console 2 to custom games
Hover over options with console 2
As console 1 backs out hit A/X with console 2
If you timed it right you now have the stack
Search for a game with console 1 and use NetDuma or other GeoFilter router to get empty lobby
Leave without party with Console 1
Console 2 sets map/gamemode/gamerules
Join with all the other consoles/controllers to fill or start the lobby
GG