Any solution here, I’m facing the exact situation after updating to nothing os 4.0 in nothing phone 2a.
Media apps will not respond when clicking on volume button and button stays unresponsive, phone screen stays unresponsive, even controlling volume from accessibility menu freeze the screen.
This was happening 2 or 3 times in a day.
After 10 mins device gets auto restart on its own. Or we need to perform hard restart manually.