employee shares a file with an external user (only sharing to a specific person is allowed, no anonymous sharing) a guest user gets automatically created in our Azure AD

employee shares a file with an external user (only sharing to a specific person is allowed, no anonymous sharing) a guest user gets automatically created in our Azure AD
Solution outside of 365 for sharing files to external people without having to deal with AD is Zapa Client Portals . Straightforward secure file sharing, and you can easily add as many employees as you want. Invitees or guests are restricted to only seeing and interacting with files in the portal they were invited too.