As we don’t know if Halo Infinite is going to have a battle Royale mode, many game with it have copied it like fortnite, black ops 4 and now battlefield V and other mobile games. Black Ops 4 blackout mode isn’t going well. I honestly don’t think Halo should have it because it would be a copy then and 343 realized their mistakes in the Halo 4 multiplayer. Battle Royale mode would be different and nit really a proper one in Halo.
Halo 2,3 and Reach were huge successful multiplayers, only problem with Reach was loadouts and Spartan abilities. Halo 5 was a good multiplayer but declined quick due to awful release. I think the battle Royale mode in Halo would decline easily and be pointless.