Was always working fine with: Broadcom Corporation BCM4352 802.11ac Wireless Network Adapter [14e4:43b1] (rev 03) Not completely sure if problem was there already but I once got out of battery (which was maybe first time ever...), maybe that is when problem started. Anyway, tried deinstall and reinstall of drivers, and suggestions done here Dell XPS 14 9434 laptop Wifi Adapter Disabled and I can't enable it? (and in the links mentioned therein, o.a. rfkill unblock all). But still I can not switch on the wifi.
It is looking grim right now.