I kind of do something similar, but rather than have the phone in DND mode, I use an app to block and send all calls to voicemail by default. I can turn it off

I kind of do something similar, but rather than have the phone in DND mode, I use an app to block and send all calls to voicemail by default. I can turn it off if accepting a call, else, I'll call back if and when I feel like it. Another useful feature for me is an app to customize the LED lights, so I can assign different colors and blink rates for different apps and different types of notifications. These two things really make me feel like I'm in full control, and make my phone experience infinitely better.