If I'm in charge of each conference:
ACC: Getting Notre Dame is pretty much a do or die proposition. Gotta go all in on them, give them what they want. Imo the ACC can survive all this but they need ND. If they get ND, they could then go poach 3 others - I'd go for TCU, UH, and WVU, Cincy, or UCF. That would be a good conference.
SEC: I don't really think this changes much tbh. SEC is still easily the top dog with the TX/OU additions. If some ACC schools are interested, cool, but no need to do anything.
Big 10: Go for ND, Oregon, and UW, in that order. (as a fan, I hate the addition of West Coast teams but whatever) Could also look at Cincy, WVU, Kansas.
Pac / Big 12: Have to merge together. Probably too many schools to do that now which is where the ACC poaching a few Big 12 schools could actually be mutually beneficial. Pretty much no way they can catch the other 3 at this point, but they could remain relevant by merging.