When searing on google I found there used to be a way to edit the files to stop companions from leaving. However, I can't find any new threads about this. So I wonder if it's still possible?

Reason for this, is that I want to try a game with a big party of just companions.

Edit: I decided to try this from a post in 2018;
"Open triggers.txt

To disable companions from leaving, search for

144115188075855884 1224979098644774918 3

and replace 1224979098644774918 with 0

save the file"

I used cheats to quickly gather all 20 companions. Waiter for each of them to complain about the person whom they hate. After that was done, I ran around the map (cheats turned off) and fought bandits to trigger more of their conversations.
So about a save 100 days in, nobody has left the party. So I think the above guide works for anything whos interested.