I think I see my issue, and it’s mostly due to my ignorance.
I generally include all the Mozzi includes that get added when you add the library with the drop down menu. I see now that there are already includes for mozzi in the sketch, and adding all of them causes the issues above. If I add the arcore board definition, select it as the current board for compilation, add the DAC library, don’t add includes and leave the includes already there, the sketch compiles. I haven’t tried uploading and testing yet, I bet it will work. If it doesn’t I will let you know.
Thanks to Liam for the support, and of course you too, Davide.