In more common terms, it's either a grade 3, 4, or 5 AC joint separation that will require surgery.
It goes without saying, but it's very painful, and recovery is a very slow and painful process as well.
Best of luck to Mr. Buchner, to as swift and full of a healing process possible.
Link: https://irish.nbcsports.com/2022/09/12/notre-dame-qb-tyler-buchner-out-for-season-with-shoulder-injury-drew-pyne-to-start/