I agree with both Mike and Gernot.
I think what might help here is to separate the idea of the MC embracing the Solution (Change Resolve), and the MC Throughline resolving all of its conflict. You can show them moving toward Change and their Solution early, but you need to keep up some kind of conflict around their personal issues, so that we're not sure whether they might "change back". Maybe this could be handled with some other characters that don't like how the MC is Changing, maybe they don't like the IC's influence on the MC and say so, that kind of thing.
A good thread to check out would be Mike's "Taste of Change" one:
That thread gives examples of stories where the MC embraces their solution and wavers toward Change a lot early, but "changes back" and ultimately remains steadfast. You can see the similarity to your idea -- it would be like one of those stories in which the conflict is still there after their change, but in your idea they would stick with the IC's influence / perspective and remain Changed at the end. The Devil Wears Prada is a good example because you can see how her boyfriend and other friends offer conflict and pull on the part of the MC that wants to remain Steadfast. You would want a similar pull, from other characters or situations or something.
I think this will be tricky but if it's an important part of the idea you have I say go for it!