As a matter of fact, απόλυτος επαγγελματίας is still considered to be an Anglicism and somewhat colloquial. Put an article before it:
Είσαι ο απόλυτος επαγγελματίας!
However, I'd consider απόλυτα επαγγελματίας to be bad Greek. It is as if επαγγελματίας were an adjective and απόλυτα is placed before it as an adverb. However, we'd never say, say, "άψογα επαγγελματίας", so that use is not recommended.