Is there any way to economically kill enemies that are playing dead?

Just starting out the game, about three hours in, and I keep finding enemies that play dead and act like corpses, only to get up and attack when you're supposed to not be expecting it.

The problem is, despite seeing the enemy and seeing the ambush, I have no way to get rid of them without wasting a ton of ammo or triggering the ambush. I hate wasting ammo, but melee attacks don't seem to do much and in order to stealth kill them and save the ammo I need to trigger them first which means I end up getting ambushed anyway. It's a little frustrating to not have the equivalent of the match from the first game that dealt with sleeping enemies.

Is there any economical way to deal with sleeping enemies without triggering the ambush or wasting ammo?

Having beaten the game, there's no equivalent to matches that can down sleeping enemies. The way I ended up dealing with them is getting the Ambush ability, slapping the enemy with the knife, running to the nearest corner to break line-of-sight while they got up, and then ambushing the enemy as they walk forward.

The way the AI works, usually, is the enemy will know where you are and try to reach you, but unless they see you after they wake up the enemy will technically count as unaware of you, allowing you to ambush.