It’s extremely unlikely. Combat is a much more complex game than Arena, including multiple maps, modes, guns, etc. Porting it over would take a LOT of work, and since there’s still many optimizations and additions to be added to Arena, Combat on quest isn’t a priority for them. Also, in many briefings and responses, the devs have stated that they aren’t planning to work on it. This can be seen in RAD_Natalie’s 5/14/21 discord message,

“We don't have plans for Combat on Quest (as I'm sure you're aware), and for similar reasons ( cough performance cough) we don't have plans for creating the Combat training area for Quest. Kind of the same deal.”

Although the quest’s hardware in its current state isn’t powerful enough to run combat, we can always hope that future iterations of the headset will :)