Pico / ESP8266 newbie (idiot?) question !

You need to do the require().connect(...), not just require, sorry for unclearness. If you don't call connect, there's nothing there - connect is what gives you the wifi object.

Also, easier command is wifi.getVersion()

You can fire that off from the callback in connect().

I was posting that from the phone while waiting, and didn't do a very good job of giving a helpful post.