802.1x on Mac

802.1x is an authentication standard. It provides a way to tunnel EAP (Extensible Authentication Protocol) between clients that want access, and authentication servers (typically RADIUS servers) that determine whom to let in.

One of the methods people use with 802.1x is certificate-based. You have a Windows-based authentication server issue certificates to be installed on Windows client PCs. When the PCs try to connect to a protected WiFi network, instead of popping up a request for a password, they use the certificates to authenticate themselves to the network.

The message suggests to me that there is no profile installed on your system - that Apple is simply trying to give you a hint as to how you would get one if you wanted or needed one.

I've never done anything with it as all our Macs operate with 802.11ac. I understand 802.11ax is available if you have all the proper gear.

https://www.securew2.com/solutions/802-1x

What you see is a standard listing on all our Macs I assume for future use or current use if you're using a RADIUS server.

Could this be an indication someone is in my network?

No.

How can I remove this authentication certificate if the reset did not?

The information you posted does not indicate the presence of one.