I reported DND & Volume control issue so many times on customer support, they always came up with basic troubleshooting steps
Another solution provided by customer is support is that Wait for upcoming update,
Now Nothing is released 2.5.2 update still issue was not resolved.
I’m using moto g60(midrange mobile) previously which is also stock Android smartphone.
In that basic android functions is working flawlessly.
And now I’m so much disappointed with Nothing phone 2 which you called flag ship it won’t deserve to be honest