This article was inspired by the Idea posted here.
The attached macro will use the Field Info Tool and a formula to calculate the Excel column letter, e.g., for 755th field, the returned letters would be "ACA".
The attached workflow is a test to generate some number of fields.
The macro also has the ability to return sample data so you can see some sample contents as well.
Attached in the v 10.5 assets Column Letter.yxmc and example use of Column Letter.yxmd.