You found your key to not get distracted. Superrrr!
DND: I go for the old method, before the DND feature was invented. I simply switch the sound off, do this already for more than 15 years. By now people are used to me not picking up my phone when they call, or read their chat message when the arrive, let alone I do not responding quickly. This was a journey, not only for myself but also for others to accept the way I am handling that thing that is always with me, but rarely interrupts me with whatever I am doing.
The result: More quality time for whatever tasks I set out do and more depth and connection with the tasks I am handling/executing. I can recommend this to everybody.