I'm facing the same error on Debian testing running on a Lenovo ThinkPad E490.
root@maelcum:~# uname -a Linux maelcum 5.4.0-2-amd64 #1 SMP Debian 5.4.8-1 (2020-01-05) x86_64 GNU/Linux root@maelcum:~# lshw --------------------------cut-------------------------------- *-generic UNCLAIMED description: Unassigned class product: RTL8822BE 802.11a/b/g/n/ac WiFi adapter vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:05:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress cap_list configuration: latency=0 resources: ioport:2000(size=256) memory:b1200000-b120ffff --------------------------cut-------------------------------- root@maelcum:~# dpkg -l firmware-realtek ii firmware-realtek 20190717-2 all Binary firmware for Realtek wired/wifi/BT adapters