May i know which instruction you followed? Are you showing data from meta or any other place?

Current method what wordpress use to search users cannot combine display name search with meta search. But we can search user first name and last name with meta search.

Do you have knowledge in php and how wordpress meta search works? If yes i can give you idea to achieve what you want. Otherwise if you want me to write code for you, It may delay couple of days. Or you can contact through https://www.shamimsplugins.com/hire/