SMS/text notifications not working when near Mac

I am not receiving audible notifications for text messages on iPhone when near one of my Macs. Often I am in the same room with my Mac, but not sitting right at it. I want the iPhone to always give me an audible alert when a message is received.

When my iPhone is near my MacMini, iMessage alerts are silenced on my phone. I surmise that this is due to Continuity and Handoff realizing that I don't need multiple notifications on multiple devices. I have investigated both these and all appears to be correct.

However, the issue is that my text messages notifications, which I do NOT receive on my Mac, are also suppressed and until I manually look at my phone later, I don't realize that I got any.

I am using a Mac mini (late-2014), iPhone 7. This is my work location.

(When I am near my iMac at home, the message alerts on the iPhone work just fine.)

Please help me with this. My wife thinks I am ignoring her texts while I am at work.

Here are some similar threads with suggestions that have not worked for me.

SMS notifications not working when near M… - Apple Community

No text sound on phone while near compute… - Apple Community

text message not making a sound - Apple Community

My guess is there is a problem on the MacMini with the Messaging app.

I do not see anything in the Preferences in Messages on the Mac Mini that would do this.

I have rebooted both the phone and MacMini many times.

Since the text message alert works fine when I am near my iMac at home, but not with my MacMini at work, I assume this is a problem with the MacMini, but maybe not.

On the iPhone -- Text Message Forwarding is turned off for all devices.

on the iPhone under Notification, I have all alerts for Messaging turned on.

On the iPhone Do Not Disturb is turned off.

I am willing to take any suggestions, even ones I have already done.