They are essentially equal today. Based on what I can discern from the article below, ESPN will kick in more money for the ACC as part of picking up their option to televise the ACC through 2036 if the ACC creates more marquee matchups among the top ACC teams and with Notre Dame. So it looks the ACC schools will be able to earn a bit more on average as compared to the Big 12, but we will have to wait and see. The top tier ACC schools will earn far more than the bottom tier ACC schools under their proposed new distribution argreement (which hasn't been finalized).
If that's not unsettling enough for the bottom tier ACC schools, "Clemson and Florida State are asking the ACC to agree to reduce penalties for exiting the grant of rights after 2031, when TV contracts for the Big Ten, SEC and Big 12 are set to expire."
ESPN has agreed to pick up its option to broadcast ACC sports through 2036. The decision comes as the ACC works toward settling lawsuits by Clemson and Florida State.
www.espn.com