The Prophet ﷺ forbade anyone from combining his name and his kunya, naming a child Muhammad and giving him the kunya Abu al-Qasim.
أن النبي ﷺ نهى أن يجمع أحد بين اسمه وكنيته، ويسمي محمدا أبا القاسم.
Reported by Tirmidhi (2841), Ahmad (9598), and Ibn Hibban (5814), all through routes from Ibn Ajlan, from his father, from Abu Hurairah, who mentioned it. The wording is Tirmidhi's. Its chain of transmission is hasan because of Muhammad bin Ajlan and his father, for both of them are truthful narrators.