Assuming that you’ve either found a solution by now or moved on this is for anyone else the is looking for similar information. There are examples of querying posts by repeater sub fields here https://www.advancedcustomfields.com/resources/query-posts-custom-fields/ and here https://www.advancedcustomfields.com/resources/querying-the-database-for-repeater-sub-field-values/ using different methods.
