wifi not showing up

Yes that has happened to me before. Some nintendo switches depending on when you bought it, are compatible with only 2.4ghz wifi or 5ghz wifi. And now some routers are all wifi6 thats supposed to be great new technology and all but sadly the nintendo sometimes doesnt find it. Try logging into your router with another device to view your wifi settings on your router. Then try to broadcast to a 2.4 ghz wifi signal. Or try 5ghz. Some routers are "automatic" and supposedly send either signal depending on device, but this doesnt always work that way.

If last resort, try turning the nintendo off and back on and standing at different distances from your router. . Or not distances but just resetting the switch over and over til it connects. Also try restarting your router and turning the wifi off on all other devices in your home... if possible. This happened to my switch and sometimes it would connect, while not other times. For some reason it would help when it was far away on the dock in the livingroom tv which is far from the router. The 2.4 ghz is supposed to be good for distance so the router switches to it when you're far automatically.

Hope this helps

Good luck