Keep in mind that is was reported during the expansion talks earlier this year that part of the reason that the ACC expanded was to keep it in a place that even if some schools left that it would keep them above the limit where ESPN could renegotiate the contract downward. FWIW, supposedly that number was dropping below 14 (including ND).
If FSU leaves, unless they can come to an agreement with the ACC over the GOR they will not have the legal right to broadcast their games - nor will any conference they join. All that money would go to the ACC through 2036.
They could announce now that the wanted to leave and pay the exit fee - approx $120M, but ACC would still own their broadcast rights.
No conference would touch them unless they can get their broadcast rights back and even then, whether they could get a full share from the B1G or SEC is not a given. Washington and Oregon only got $30M from the B1G. Good chance that is about what FSU would get on the open market.
The GoR does not have any provisions which allow a school to leave and get their broadcast rights back. FSU would have to sue and take their chances where the ACC likely holds almost all the cards. FSU has signed the GoR multiple times (negating any defense of being 'forced' to sign) and is unlikely to win in court. Their only real option would be to sue and then hope they could negotiate a deal before it went to trial (which could take years).
The beauty of the GoR is its simplicity. The whole document is only 3 pages. It basically says the signees have agreed to give their broadcast rights to the ACC through the end of the media contract. There is no provision in the legal document for getting those rights back. Once you signed it, you have agreed to give up your media rights with no rights to get them back until 2036. It is reportedly the same basic GoR that both the B12 and PAC had/have and shows you why no school yet has tried to challenge one. I guarantee at least 30 schools have had lawyers look at those documents and no one has found a 'loophole' yet.
I would also suspect that the ACC would vote to withhold any future payments to FSU as soon as they made an announcement of departure.
Texas and OK ultimately negotiated with the B12 to pay $50M each to be able to leave 1 year early. If FSU did something similar they would be looking at paying the ACC $650M.
They are also getting angry over a system that no longer exists. If the same situation came to pass next year they would be in the CFP win or lose the ACC CG. They seem so blinded by anger and entitlement that they are missing the bigger picture.