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.