This is absolutely possible, even currently - albeit in a very much non-portable way. For example boost::pfr and my own (wip) repr library have the required machinery for this.
> Boost.PFR library works with types that satisfy the requirements of SimpleAggregate: aggregate types without base classes, const fields, references, or C arrays:
And in general seems to be dependent on C++20 for getting field names.
Do you know how this works? Initializer lists seem somehow involved.