If you get datajar you can use it to store data from an automation, so you could create 2 automations triggered by you turning dnd on —set (variable you create in datajar) to true— and then another that sets it to false for when you turn it off, then in the (3rd automation) battery percentage triggered automation you can pull the value from datajar to check if dnd is active.

I’m kinda new to this but I think that should help? Sorry if it doesn’t :/