Wifi is missing in the network interface popup

It is possible that the WiFi cord got damaged by surge. Bring it in to an authorized service center to take a look at to ensure that it is properly connected to the WiFi card on the logicboard. It is very easy to damage these things if you don't know what you are doing.

A simpler solution would be to add a USB-WiFi dongle.

Yes. But as you can see in the image I'm showing, most typical WiFi cards aren't just inserted in the internal port, but also depend on cables to attach to their round terminal ports. These can get damaged with a surge, or improper install. That's why it pays to have a service technician verify why the WiFi is not showing up, especially with older computers:

These are electrostatically sensitive equipment, and take a lot of delicate work to access. And while your machine is under warranty, it is good to have it looked at it regardless by an authorized service provider.

Only for Continuity Purposes 😎

Cannot see which interfacing the network … - Apple Community