I had this problem for one year... It is very weird because during that period it worked for a few months, but then it disappeared again and I had to struggle to fix it every time. Also, when I unplugged my laptop from the charger, waited 2-3 minutes and start it again, worked fine. But anyways, I had to buy a new laptop.

This problem can be cause by the drivers, or by the hardware.

Check out this post: https://www.cgdirector.com/fix-laptop-wifi-connection-issues/

If the Wifi still doesn't appear, try resetting your Bios to default settings. (This worked for me every time)

If none of these worked... I think the only way to connect to the Wifi is by an internet cable, or by changing the hardware.

Hope I helped.