This post has some KQL to report usage of Internet Explorer.
Defender for Endpoint is a terrific source of data for IT Operations. Within M365 Defender for Endpoint Advanced Hunting you can build KQL queries to drill down into your data.
KQL to find usage of Internet Explorer in your organisation
Example KQL find which intranet sites are still frequented by people using Internet Explorer.
Find more IT Infrastructure tips at blog.alexmags.com