Hey @Ekveel !
If you want specifically that order (i.e. keyboard controls player 1 and gamepad controls player 2) you can use an option in the project settings just for that.
If you want it to be related to when an input presses the start button, then the problem could be related to the player controller, you may need to spawn a player controller as well as the pawn when you create it. Then possess the pawn using that player controller.