Thank you for the prompt response. In my tests, I could only filter on recipientEmailAddress when also providing value for networkMessageId. In other words this works:
https://graph.microsoft.com/beta/security/collaboration/analyzedEmails?$filter=networkMessageId eq '95b7cb80-d5ec-4bf8-7890-08dcb49ac475' and recipientEmailAddress eq 'email address removed for privacy reasons'
but this does not:
https://graph.microsoft.com/beta/security/collaboration/analyzedEmails?$filter=recipientEmailAddress eq 'email address removed for privacy reasons'
I'm also not having any success with $count, I only ever see @odata.count added to the response when I run it without any parameters. Would be nice if the documentation can be updated with some examples on that and filtering 🙂