I am using an AsRock x370 Taichi motherboard, and Ubuntu doesn't seem to be able to detect the embedded 802.11 module. It looks like it is able, however, to use the bluetooth module. The WLAN module's manufacturer is Intel.
For those that stumble upon this question with the same issue. I was able to solve this with the command given in cheche's answer to How do I get an Intel Wireless 3168 802.11ac wireless card to work?
apt install linux-generic-hwe-16.04