You may not have heard the news. Basically the tldr. Pubg feels epic should have contacted them before making a last man standing game mode.
Just google Epic bluehole fortnite.
So that bit of a tiff may have something to do with your template not being accepted.
I think either the big wrestling company or hunger games may have ownership of battle royale.
You can call it Deathmatch as ID software really doesnt seem to care about trademarking a gamemode.
Maybe Royale deathmatch template