I don’t see any way they overturn all these nullifications of state laws and amendments. The best we can hope for is that they somehow define the issue narrowly within the actual law. That somehow they say because the government provides services and tax breaks to couples, they have to apply the same to a gay couple, but that states have leeway to define it in a matter seen fit. Also some sort of religious freedom discussion. That is highly optimistic, but it’s the best we should even hope for. .
Like you, I hope for a narrow ruling that protects religious freedom. I’m not optimistic about that, but it isn’t out of the realm of possibility.