I'm trying to really see what you're saying about all this but as I see it from the other side, I know that Christians who create art about Jesus are also blessed by God and oftentimes the Church has commissioned the piece. How is that different from an icon?
The difference may be in the consecration of the iconographer, the consecration of the icon, and the use to which it is put...
If you are asking me to define the difference in God's Grace accruing to a person who paints or creates his or her version of "Christian Art" and that accruing to the iconographer creating icons for Ekklesiastical worship, I do not know how to do so... If you create an image of Jesus and find God's Blessings in your life as a consequence, or at least a presumed consequence, then that will be a private matter between you and God... Similarly for the Blessing accruing to an iconographer from God in his creation and dedication of his iconographic works...
You see, our icons are out of the Faith of Christ in His Body, the Ekklesia...
They are blessed by the Priest...
They are written by the iconographer...
Working thus in the Blessing of the Body of Christ...
They are thus not a private works of art...
They are not private versions of an artist's imaginative depiction...
They are highly stylized requiring specific elements...
The colors have significances...
Everything in them is prescribed to be there...
They are written in obedience, not creativity...
So if the artist and the iconographer end up with similar icons...
And if God blesses them both...
And others are impacted similarly, at least reportedly...
Then what is the difference in God's Grace?
I have no idea...
I only know that standing before an icon in prayer is standing before the person that icon depicts...
I do not know if that is true of an artist's rendition...
I would hope so...
But look - I used to spend a lot of time working my way through translations of Greek Scripture into English in a was that permitted English to function as if it were actually Greek except with English words... I would diagram the sentences, and massage the glosses, trying to get the English to behave as the Greek behaved... With differing results... But at the end of spending 30 minutes to an hour on a sentence doing this, I felt a lot closer to God for having done so... I experienced His Grace...
I think you will do so as well with the time you spend in the treasury of your heart creating Christian Art...
And for that, as a private matter, you should do well - Time spent in Christian concerns is a good thing...
I really cannot take it much further than that, for I simply do not know...
I do know that Icons are the Sacred Art of the Church...
And they are different than simply Christian Artists creating Christian Art...
I know a (now reposed) Christian singer who created Christian Songs our of Bible stories and other writings...
I saw her as a singer of Christian Folk Art... It was not the Ekklesiastical Chanting of the Church...
Here she sings her song to her Guardian Angel:
https://www.youtube.com/watch?v=VQ06tEP_wUI
And here she is singing her song of the Czar Nicholas and his family at the time of their being martyred by the Atheists...
https://www.youtube.com/watch?v=JoDUIBfECpg
These are artistic and pious renditions...
They are not Ekklesiastical Music of the Church...
The difference is that between the Heavenly Food that is our Lord...
And the delicious food from our kitchens...
I suspect the difference is similar for Icons and private Christian Art...
Arsenios