'Paul' could have written in 20 BCE.
The 'Christ' of Hellenistic Jewish theological philosophers had been around at least since 150 BCE (Dan 9:25-26 > LXX "Christus")
There is not a writing of 'Paul' that can be determined to be genuine and free from latter interpolations, additions, and editing.
Just because an occasional obligatory 'Jesus' gets stuffed in here or there is no indication that it was present within 'Paul's' original untampered with 'Christological' monograph.