I’m thinking that doing this in the code could make ACF store and retrieve the values from the same place.
ACF stores the subfields of a flex field in the database as
$fex_field_name.'_'.$row.'_'.$sub_field_name
Nothing will keep you from having to duplicate the fields if you want to have the same fields in multiple layouts, either in code or in the editor. The only thing my suggestion might do is alter the way the field data is stored in the database.
I’ve found that if I want to have lots of layouts that all use common fields that a repeater with a heavy does of conditional logic is a better choice than flexible content fields.
