[Defender Pro] Username Hackproof

I noticed that multiple attempts to unethically log into my site involved the usernames of my authors, including the renamed admin user. It seems that there are methods of query that allow unethical parties to discover user names. So just removing admin and making a new cleverly named funkycooladmin doesn't work, as they have ways of discovering user names, here is one…

https://www.wp-tweaks.com/hackers-can-find-your-wordpress-username/

My request is that the defender tool addresses this issue as well. I know it is locking them out, but they are using new ips and are relentless. Now that they know my custom admin username they now just need to Brute force against passwords with many new IPs. I assume there is a way to stop the discovery of usernames.