A comment @pete_c made in a recent discussion regarding the inability to compare the result of one EA to another reminded me I created a Feature Request a few years ago for that capability: Support a 2nd Extension Attribute as the Value when using Extension Attribute Criteria
Anyone who has ever dealt with the email configuration option for installing the Netskope agent probably recognizes the original trigger for this request, but I suspect people would find more if it were available. I don't recall when the status was changed to "Reviewing", but with only 5 votes at this point it's not likely to be getting much review so this post is a request to any readers to upvote the request. I don't know if it'll actually help, but it can't hurt :-)
You said Netskope and made me get a little sick, on nondomain bound macs it really had no idea what it was doing. Using a configuration profile to define the logged in users Email Address when the client was installed was dumb enough, but then having no way to update that email address without reinstalling the client was stupid. I am so glad we got rid of that client earlier this year.
Anywho, up vote given.