No Wi-Fi Adapter Found : 3 Delta, Ubuntu18.04

Hi,

I installed Ubuntu18.04 on LattePanda 3 Delta, and found Wi-Fi is not working at all, even though wired connection works normally.

Wi-Fi icon on upper-right corner of the Desktop is not shown. Wi-Fi settings window says "No Wi-Fi Adapter Found".

Wi-Fi module on 3 Delta seems to be AX201D2W, so I tried installing the firmware for "Intel® Wi-Fi 6 AX201 160MHz" from this page: https://www.intel.com/content/www/us/en/support/articles/000005511/wireless.html

but nothing changed. (Actually the same firmware files were already there.)

Any advice to fix the problem?

Distro: Ubuntu 18.04.6 LTS

Kernel: 5.4.0-135-generic

lshw -C network:

  *-network UNCLAIMED       
      description: Network controller
      product: Intel Corporation
      vendor: Intel Corporation
      physical id: 14.3
      bus info: pci@0000:00:14.3
      version: 01
      width: 64 bits
      clock: 33MHz
      capabilities: pm msi pciexpress msix cap_list
      configuration: latency=0
      resources: iomemory:600-5ff memory:6001114000-6001117fff
 *-network
      description: Ethernet interface
      product: I211 Gigabit Network Connection
      vendor: Intel Corporation
      physical id: 0
      bus info: pci@0000:01:00.0
      logical name: enp1s0
      version: 03
      serial: 00:e0:4c:0c:34:68
      size: 1Gbit/s
      capacity: 1Gbit/s
      width: 32 bits
      clock: 33MHz
      capabilities: pm msi msix pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
      configuration: autonegotiation=on broadcast=yes driver=igb driverversion=5.6.0-k duplex=full firmware=0. 6-2 ip=192.168.11.12 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
      resources: irq:18 memory:7fc00000-7fc1ffff ioport:3000(size=32) memory:7fc20000-7fc23fff