There are no duties to self; there are rather 2nd-order desires whose satisfaction partly builds and partly reveals one’s personality.
Interpersonal duties are perfect: one must never steal; acting on 2nd-order desires is an imperfect imperative in Kantian terms; one is at times permitted not to seek self-perfection.
No particular personal virtue must be pursued, even imperfectly, since one needs to specialize even regarding character, in the way that one must not commit any crime.
Duties by their nature must be done regardless of desires; 2nd-order desires compete for satisfaction with 1st-order desires. In other words, duties motivate by demanding that wicked desires be suppressed; it’s always an individual choice whether to seek the satisfaction of incompatible 2nd- or 1st-order desires.