What worked was download and install the CMAKE Mac app, then apply this voodoo I found on the web:
sudo "/Applications/CMake.app/Contents/bin/cmake-gui" --install=/usr/local/bin
Why your shell can’t see an installed app on a Mac is Mac OS stupidity. (Sorry, have not been working on a Mac long enough yet to be fully gaslighted).
Deps, Rack, and plugins happily fully built while I was typing this. (damn, that was fast! This part of running on an M2 CPU is awesome).
Thanks everyone for the help!