If the sound department has nothing else to do until launch ( ), I would propose a suggestion to make play sessions with the same civ less repetitive:
The battle music should switch to the enemy team’s strongest player’s theme when the enemy is dominating the match.
Different circumstances could trigger this, like the enemy having a huge score lead, steamrolling the player’s base or holding sacred sites/wonders.
It could make the enemy more imposing while turning the tide would be very rewarding music-wise.
Here some AOE4 battle music:
Bonus: Spectator Music
If you add a neutral player as spectator later down the line, it would be neat if it comes with its own music (derived from the AOE4 main theme) while adding certain instruments to the peace/war music when the corresponding faction is on screen.