Some updates here. I have tried a couple things to resolve my Bluetooth issue on my M1Max MBP 14:
I tried running the AirPods Max off the computer with nothing else connected to it, unplugged from the dock. No joy, after a few minutes the same BT cutouts occurred.
I turned off BT on my phone, put my iPad and Watch in another room. I turned off the nearby Windows computer as well as the AppleTV to try to get any other BT item from creating an issue. Still same issues with all this.
I am certain i the problem is with the Mac itself, all 3 AirPods (Original, Pro and Max) models exhibit the same behavior and all 3 sets work fine on the iPhone and iPad.
I am now trying the AirPods Max on a new (to me) Intel MacBook Pro 15" 2017 my son gave me. So far so good but it has only been an hour or so. I may try this on my wife's MBP M1Max 16" next.
I am still looking for some sort of external BT dongle that will work with the Mac, I am still open for suggestions on that.
The saga continues.