There is an explanation of how to do this on this page https://www.advancedcustomfields.com/resources/query-posts-custom-fields/ 4. Sub custom fields values and there is a conversation here, the last comment tells you how to fix the example so that it works https://support.advancedcustomfields.com/forums/topic/percentage-in-sql/
Or you can follow my advice here https://acfextras.com/dont-query-repeaters/
