Only Serious Modes in the Beta?

I have scoured the internet for a way to customize my Playlist, like Halo:MCC, because I only like to play very specific modes that are really chill, but it appears there is no way to do that.

I understand it is a Beta test for the Multiplayer, but I have very little trust in game devs in general and 343 and am worried that this feature won’t be included in the full multiplayer. Does anyone know if we will get to choose the game mode we want when it launches full?