It's not really about time, it's more about shutting off your brain or not.
Anyway I guess you never played Blackguards ? Sometimes ennemies turns were very very boring because you had many ennemies and nothing to do during their turn (as in every TB games)... but that's not really what I pointed at.
The alternative is to not shut down your brain, but always be thinking about plans and contingencies. More often than not you’ll know what you want to do as soon as they’re done.