Closely related: Excluding properties from automatic Codable
I believe the best way to address this and similar problems would be, like @anon31136981 writes in the linked thread, a general annotation/decoration mechanism where variables (maybe also functions/types) can be annotated with arbitrary information, e.g. a coding strategy, a marker to ignore a property completely for coding, etc, that Codable synthesis (or maybe something at runtime?) could then use.