How can I fix a greyed out Wi-Fi button on Mac mini?

So…….

Had to factory reset my Mac and all was well but the Wi-Fi will not turn on as MacOS has greyed the switch off. I have checked System Information and it does not say “No WiFi hardware found!”

What is causing this?? I have restarted 3 times and have reinstalled MacOS yet the problem will not go away. Each time I try to reinstall it from an external hard tube it tells me I need Wi-Fi. Catch 22 situation

[Re-Titled by Moderator]

Original Title: Wifi button is greyed out