Framework mainboards with 12th gen Intel CPUs have yet to become available. For repairing or replacement purposes, however, these 11th gen CPU mainboards are now on sale complete with CAD and electrical documentation for tinkerers.
https://www.notebookcheck.net/Framework-Laptop-mainboard-is-now-available-directly-from-the-company-starting-at-400-USD.615138.0.html