What are the authentic Pauline texts scholars argue about the most especially in the Corinthians, Romans, and Galatians?
That's covering a whole lot of issues, which there aren't any strong arguments about if the topic is authenticity of Pauline texts. The Book of Hebrews is more likely, the issue is the author(s). But you picked three that I have heard no serious challenge against Paul being the author of those letters, the three you name. Granted there might have been an amanuensis involved.
All are Scripture, and the CHURCH never judges based on attribution. Not one of the Gospels says who wrote them, not one.
I don't pay particular attention to fringe groups. I accept all the writings attributed to Paul, as most theological Bible scholars do.