I have so many question about this.
Our gateway filters are standard Microsoft, and they are absolutely terrible. We have two junk mail filters, one in the gateway, one in outlook, and neither seem to catch any significant amount of junk (both are pathetic compared to Gmail, for example)|.
Why are internal emails filtered out? I have never understood this. Internal emails should be secure. If you have an internal account sending phishing emails, you are already breached, and you have bigger problems than to filter out emails.
Finally, what is the issue with links? Links should be safe to click. If links are not safe, you have a security problem already. It is what you do next that is the problem.