Sorry I disappeared. I gave up.
But a pandemic tends to focus you...
I finally worked around by manually assigning it. The odd thing is "Shift-Cmd-=" didn't work, and something else failed. It was making the "View" tab above highlight. Note, the "Cmd='" didn't;t ring the warning bell - something liked it.
I have my silicone Lightroom keyboard overlay, I scanned it for something unused... ":" (Shift-

. I assigned "Photo→Create Virtual Copy" to "Shift-Cmd-;" - got me why that one worked. :-/