Is it Mustahab, Sunnah or Obligatory?
Jazak Allah Khair
The ruling of covering the head for men goes back to people’s custom. If it is something that is considered part of beautification, then the head should be covered, especially in Salah, and this would be considered recommended.
However, if the custom is that people do not cover their heads, then there is no harm in not covering the head.
And Allah knows best