If you only have the UID of the user, with this tool you can get the user information (email, givenname, surname, department).
in the appsettings file you need a valid appregistration clientid and secret that has access to the Azure AD properties.
"TenantId": "",
"ClientId": "",
"ClientSecret": ""
Use dotnet run in the project folder and paste the GUID's split by ',', ';' or '\n' (comma, semicolon or linebreak) in the textarea and click Lookup