My phone doesn't talk to my PC so that's not an option.
I've given up on Xposed because it isn't listed in the Google Play Store, at least not anymore. I would be happy to try a similar program.
My quest continues
I did discover a work-around the volume warning. Hold the volume-up key until and as the warning displays, keep holding it and tap "ok". The warning will not appear again until you restart your device.
...but it will appear again after the device is restarted, so I still need a way to remove it from existence.
Throughout the day I need to stop and talk to people. No one notices
(or at least I haven't noticed them noticing) when I lower the volume of my phone in the front pocket. When I want to raise the volume again I'd like to be able to to just hold the volume-up button, but this warning keeps getting in the way. To dismiss the warning I have to take me phone out of my pocket, which lets everyone see that I have a phone despite the no cell-phone policy.
And before everyone gets in a huff about respecting the employer's policies, everyone has a cell phone despite the policy, even the supers and managers, and there is a very big "
just don't make it my problem" unwritten rule.
My efforts are to be sure it never becomes my employer's problem.