Thank you for your hints the solution was adding typename before one<_Return>::UseType (*)(void);
so that it looks like:

using PF = typename one<_Return>::UseType (*)(void);

Here is a link with more info type_alias

Additionally, class one has to be defined as @RemyLebeau suggested:

template <class _Type>
class one {
    public:
      using UseType = _Type;

};

by some reason _Type, and _Return was not a problem. Maybe because in the case of templates they are reduced to local scope, it's just a guess.