How to automate “do not disturb”

It's my understanding that this is by design.

Do Not Disturb mode is meant to be active when the phone is not actively in use. The idea behind it is that, if the phone is unlocked and you are working with it, you do in fact WANT to be notified of a new item. However, when the phone is locked and dormant, the logic is that you no longer wish to be disturbed, and it will suppress vibration / notification indicators.

So for example, if you are sleeping, and DND is on, then it will remain silent, and not vibrate. If you roll over, pick up your phone to check messages, and it's active, the DND will still allow vibrate to indicate new messages while you are using it.

One workaround that I see a lot is to ask your workplace for a dedicated work phone - if they expect you to be reachable outside of office hours, then they've likely got some legal obligation to provide this.

When you're not working, turn it off.

On the other hand, if you can't just let go of work when you get home, that is a whole different problem and possible solutions I can think of are to keep yourself busier by getting a new pet, child or lover. This is especially true if you already have at least one of these.