According to the knowledge that I have gathered after working in the facilities department in an organization, admin executives are those who work on the facilities side in a company. They address general issues faced by employees, such as AC control, housekeeping, cafeteria management, and medical aid. However, an admin assistant primarily assists top managers with their administrative needs, such as scheduling meetings and managing stationery requirements. In some companies, the admin assistant is supported by admin executives, so employees contact their local admin executive for help rather than going directly to the admin assistant.
Regards,
Shruti