Hi Leo,
did you check "ip l" when booting the arch live image, to see if the
interface is really not detected? Did you try unblocking it with rfkill?
Maybe there is a hardware switch on your device, or a key combination
with fn + f8 or similar?
Otherwise, it might be helpful if you'd provide the output of lspci and
lsusb, so we can check what the exact wifi model is. Also something like
dmesg|grep network or dmesg|grep wifi might be helpful :)
If Ubuntu has working wifi, it should be possible with Arch as well :)
Greetings,
Lukas from Germany
