Is it better to say "Sayyiduna Muhammad" or just "Muhammad" in the Tashahhud and during the prayers upon the Prophet?

The Prophet, peace and blessings be upon him, is the master of the children of Adam, and there is no doubt that describing him as such is correct. As for acts of worship, they are built upon adherence [to what is prescribed], so nothing that the Messenger, peace and blessings be upon him, did not legislate should be added to them. What is narrated in the Tashahhud (definition) is "and I bear witness that Muhammad is His servant and Messenger," and in sending prayers upon him [it is] "O Allah, send prayers upon Muhammad." It has not been narrated from him, peace and blessings be upon him, that he taught us to say "Sayyiduna" (our master), and this is preferable. Adhering to the narrated wordings is more sound, and it has not been reported from the Companions, the Tabi'in, or the jurists that they used the word "Sayyiduna" in the prescribed adhkar (remembrances). All goodness lies in following [the tradition]. As for matters other than worship, there is no harm in saying "Sayyiduna Muhammad."