Since I'm asking for a self consistent framework and side effects, of which energy is just one part, I don't see this as a duplicate. I'd like to see both sides of this argument so we can decide how to treat this question, and as guidance for future askers.
I issued the close vote.
I felt that anyone looking for hard-magic ways of transmuting elements will necessarily need to deal with the general conservation of energy as the most crucial part of that framework given the massive amounts of energy involved. If you hand-wave that away then you are quickly out of the realm of hard-magic.
I also want to dissuade the whole "how would X work if Y?", "how would X work if Z?" sort of duplication where the answers are similar, but fragmented.
And I am also concerned that the question is too broad. Once you allow hand-waving something as vital as the conservation of energy, you allow many possible hand-wavy/magical answers to solve your problem. But I voted as duplicate since it's more helpful than too broad, even if the broadness helped encourage my duplicate vote when I might've otherwise considered it different enough.
The questions are inherently different
The first question is asking about the consequences of magic as achieved by violating nuclear physics or altering time, the second question is about the consequences of magic as achieved by violating thermodynamics. Labeling these the same is like labeling a question about helicopters as the duplicate of a question about rockets.
Even through the end goal may be similar, the mechanism by which you get there matters.