Turn based combat can not be used in epic large-scale battle events.
individual initiative bro. You don't have to sit there for 10 mins because only allies move.
And the point of turn based is exactly that you don't have to "watch your allies move". You're engaged in the process. I'll assume you're describing a very specific scenario, with hordes of enemies, lots of allies and just a small party under your control. But even then, that doesn't mean your party has to act totally independently of your allies.
In Suikoden Tactics (SRPG) e.g. you could change the elemental affinity of the Terrain; think D:OS. But because you tended to have lots of allies, each with their own elemental affinity, you could use your turn (or some of your turns) to assist your allies with elemental buffs/ elemental debuffs on the enemies they were facing (not even counting regular buffs). Because each elemental buff affected several squares, you had to think quite a bit about how allies and enemies are going to spend their turns and where they're going to move; you don't want to end up buffing the enemy and debuffing your allies.
In fact, this offered up two routes: either let your allies distract and bind up some enemies while your party works together to do the actual killing, or spend your turns buffing allies and debuffing their enemies while some of your own do a bit of striking as well.
If anything, all of this became way more nuanced than anything you could do in real time.
Also, if 'large scale battles' are a thing in your game, why not allow some rudimentary ally control on parts of the player? In the Goldbox games, supposedly Paladins (or anyone with high Charisma?) could make a leadership check to see if allies fell under their control. Super simple, but it already breaks up the monotony of a large scale battle if the combat system wasn't actually designed for those.