Zachary Neel of Ducks Wire cites a Forbes article, which reports that in Summer 2022:

”The ACC and Pac-12 had detailed conversations about a partnership, involving a championship football game between the two conferences, as well as other basketball and Olympic sports events that could land both leagues a better media rights deal as UCLA and USC left for the Big Ten. At the time there were too many moving parts to go further plus the ACC rights deal that pays each school 36 million dollars through 2036 seemed a massive obstacle.”

https://www.forbes.com/sites/zengernews/2023/02/20/the-pac-12s-leadership-needs-to-ink-a-new-media-deal-then-start-acc-merger-talks/?sh=b64940869734

Neel does a nice job in outlining a would be roster of such a super-conference. It includes certain athletic credentials for each program and - more importantly - TV market rankings.

https://duckswire.usatoday.com/lists/can-the-acc-save-pac-12-teams-introducing-the-apac-an-intriguing-new-conference-idea/