wifi icon gone after install probably means nm doesnt see a wifi device yet.
check:
-nmcli device
-rfkill list
-lspci -nnk | rg -i 'network|wireless|wifi'
-lsmod | rg -i 'iwlwifi|ath|mt79|rtl'
if nmcli shows wifi unavailable + rfkill soft blocked: rfkill unblock wifi. if lspci lists the card but Driver is empty, thats firmware/kernel. bios wifi disable is only worth chasing when lspci doesnt even show the device.
Is the wlan icon shown when you unplug the LAN cable?
All done. Those and other tests result in the hypothesis that it's a hardware issue. Next step is opening up the laptop itself and inspect for physical misalignments and such.
wlan icon doesnt show with unplugged cabel.
the 'wired'-icon is shown when plugged in, and not shown when unplugged.
So that works as intended 
Did You checked the ''Additional Drivers'' tab if there is a Driver offered? Could You post the Output of the Commands sudo lshw -C network and rfkill list please?
Yeah, checked all that and far more. Eventually opened the case, reseated the AX200 wifi-chip which then appeared in the traybar on screen.
Still no connection, achieved connection on one of the router-channels, but only with wap2, not wap3. That turns out to be a known issue of zorin kernel 7.xy in combination with AX200-wifi chip. The AX200-driver onboard is the most recent version known to work.
I ordered a wifi-dongle, hope that it's supported by zorin-drivers etc, forgot to check before paying.
When that's up & running I'll post a summary of the tests and trials, from the machine that then should be wirelessly online...
I think you meant WPAx. 