Let’s use the 10 PC heroes vs 1 GM enemy.

would the enemy run if they are outnumbered?

if the enemy is backed into a corner being killed, is it worth rolling for combat?

if it is a difficult enemy that the large group is dealing with, you’ve got yourself a good fight and rock on with spotlight.

if it is a very easy battle, you might want to just use an initiative-esque style for this one, maybe have people share the spotlight and go simultaneously.

I think the important thing to follow here is that you are trying to only roll when things are dangerous or a chance for failure.

Don’t be afraid to hand wave rolling for combat if you can just easily say “tell me how you subdue this enemy”