SOLVED. Did another reboot and it started working.

ok - did the installs worked, webcam tests worked fine, YouTube can see the webcam but Facebook cannot. So this is odd!

It's the wifi6 built into the Intel Core i5-1235U.

It's the wifi6 built into the Intel Core i5-1235U.

ipconfig propersly shows iwlwifi0 as wlan0, and put the ssid and 8-letter password into etc/wpa_supplicant.conf and tried starting it wia wpa_supplicant command. It fails 4-way handshake. networkmanager does not do anything. What precisely should I do?

I've plugged in a Logitec C270 usb webcam. It appears on usbconfig and shows picture on VLC on device video0 but Facebook cannot see it. I've given it permission. How can I debug this?