Used descriptively, “ʿabd Allāh” comprises “servant” and “God”: its constituent words contribute to the combined relational meaning.
Used instead as someone's proper name, “ʿAbd Allāh” is meant to identify that individual. The constituent words are not meant to signify parts of that individual's identity. In this use, the name is logically simple.
The same visible words can therefore be treated differently depending on their intended signification. What matters is the meaning conveyed in the actual use.