Popa
I know many many people who believe in what you describe as
“straw man” daas Torah. No they do do not it just as advice. Granted this “straw man” which some do believe in is extended to many such as yourself who do not believe it but, it is a real belief. Especially among Chasidim, but it has spread to non-chasidim as well.
I also do’nt understand your distinction between KEsuba and prenup regarding the problem to “plan for divorce before you are married” would you be able to elaborate?