Is it true that a person becomes what they constantly strive for and imagine with total absorption?

According to Osho, not at all: the idea that you become what you ceaselessly strive for and imagine is self-hypnosis, not awakening. There is nothing to become; your essence already is, like the Kohinoor beneath mud. Drop imaginative overlays, refine awareness, and cut away the nonessential; then reality reveals itself. Imagination paints spectacles; removing them restores clear seeing—value grows as egoic weight falls.