Did Jesus actually exist?, page-14

Regardless as to how many corruptions Constantine inflicted on Christianity, he did not invent the basic religion that he used for his own purposes.

I think you are arguing on two fronts. 1. Did Jesus exist and 2. Has Christianity been corrupted by external influences, including Sun Worship and certain pagan beliefs.

Firstly, Jesus almost certainly existed as the basis of a Christian movement. Secondly, yes.

Your argument neither supports nor denies that Christ existed as a real person. It does however suggest that a number of embellishments were added to His story to flesh Him out somewhat.