Based on what you said I'm going to turn off my automatic DND at night-time (and never use DND at all). Instead it might be better to ALWAYS keep my phone's ring/silent switch on silent (with volume still up for the alarm to ring loud). Also, I turned vibrate totally off on the phone. I have the watch always on silent. This way I totally depend on the watch's haptic feedback for notifications.
At least this way the notifications should always be received on the watch. Added benefit of never having to adjust settings on the watch or phone for meetings, etc.