In the final chapter, we summarize the key findings of the thesis, emphasizing the breakthroughs achieved in developing polyatomic molecules, particularly YbOH, as a powerful platform to search for fundamental symmetry violation. We review the progress made in molecular production, spectroscopy, and state preparation in polyatomic molecules. We also provide an outlook for the new physics reach of a precision measurement searching for the NMQM in \(^{173}\) YbOH. Finally, we reflect on the long-term vision for polyatomic molecules and outline the next steps in quantum state engineering to further enhance experimental sensitivity. This work significantly advances the field of precision measurements of fundamental symmetry violation using cold polyatomic molecules.