Repotting plants is much more stressful to plants than is commonly understood. That is what your Philodendron is reacting to and will continue to for quite a while. It is not a problem with light or nutrient deficiency. Nor is there a quick fix.
How well and how rapidly your plant recovers will depend on how much of the original soil you removed and how much the roots were disturbed. You will have to be patient and recalculate the water that it needs as a result of the repotting.