I think the scheduling bit is one part, but i think the long term play is setting up the next CFP right where ESPN doesn’t retain exclusive rights which only further helps the SEC. I don’t think the ACC network will be related to the CFP negotiations.
From the ACC’s position, they will be looking to add Notre Dame as a full member and maybe another school, keep their heavyweights from bouncing, and make sure the SEC doesn’t push them around as you mentioned above. This will require them to give in for the other two P5s schools.
The Pac-12 and Big 10 both have deals, albeit not exclusive, with ESPN and Fox. Notre Dame has NBC. Amazon has a bag and will probably try to crack CFB. I think this move will allow for a bidding war and halt an accelerated expansion which will only favor ESPN/SEC.