Is it permissible to supplicate with "O Light of all things and its Guide, You are the One whose light cleaves the darkness" for the purpose of treating delayed marriage and acquiring a beautiful face? And is this supplication forbidden or not?

This statement is correct in meaning, that Allah Almighty is the Light of the heavens and the earth and their Guide. However, supplicating with it in this specific manner for this specific purpose is an additional innovation (bid'ah idafiyyah) because it has not been transmitted in the Sunnah. Likening something not from the Sunnah to something that is from the Sunnah is an innovation. It is not recommended to supplicate with these words. Rather, whoever has a need should increase in supplication and asking.