DND with contacts excepted is good, but it has another failure mode: food delivery. They do tend to call twice, but the whole thing is more pleasant when disabling DND at time of ordering. Naturally, reenabling DND tends to happen only after the next spam call.
Yeah you can always disable it for a short time when you're expecting food, not a big deal. Just write a script that allows you to disable for 30 minutes and it auto-reenables after that.