I have installed TW on a raspberry 3B+ using the KDE appliance.  It came up
without a wlan interface - I ran a zypper dup, still no wlan. I found the
following in in dmesg:

[   19.191508] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43455-sdio
for chip BCM4345/6
[   19.192794] usbcore: registered new interface driver brcmfmac
[   19.233451] brcmfmac mmc1:0001:1: Direct firmware load for
brcm/brcmfmac43455-sdio.txt failed with error -2

bcm43xx-firmware is installed, but :

# l /lib/firmware/brcm/brcmfmac43455-sdio*
-rw-r--r-- 1 root root 488193 Jan 18 13:04
/lib/firmware/brcm/brcmfmac43455-sdio.bin
-rw-r--r-- 1 root root   1864 Jan 18 13:04
/lib/firmware/brcm/brcmfmac43455-sdio.raspberrypi,3-model-b-plus.txt

I added a symlink and rebooted. Now I have wlan.  I don't know if this is
standard procedure?