Guessed about 39 things before found it. Still have no idea why.
whimsy constructor · 2022-03-23T18:43:38.504Z
67A, 8D, and 62D are the admittedly obscure hints; in combination with 46D. Was hoping that and the rainbow of symmetric color entries would do the trick. The title is a cue to look at the letters over (above) the central letters of the colors of the rainbow.