Hi @juiceex
I believe you need to use the ‘meta_query’ option. This page should give you more idea about it: https://codex.wordpress.org/Class_Reference/WP_User_Query#Custom_Field_Parameters. You can see the example how to query posts based on custom fields here (under the “3. Multiple custom field values (array based values)” section): https://www.advancedcustomfields.com/resources/query-posts-custom-fields/#examples. Even though it is talking about posts, I believe you can do it for the users too as they have similar ‘meta_query’ option.
I hope this helps 🙂
