When I say duplicate fields I don’t necessarily mean that I’d create an ACF field on both field types that match. What I mean is that I would create a custom field using the standard WP functions like add_post_meta() with a different field name. The only purpose for this field name is to have a value to search by in the database. I outlined a similar idea about repeater fields here https://acfextras.com/dont-query-repeaters/
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