Wifi working on iPhone but not on Mac

USB 3.0 and USB 3.1 drives and devices are know to cause Wi-Fi and Bluetooth problems for the later model Mac Mini models. If you have any high speed USB drives and devices connected to the Mac Mini, try ejecting and disconnecting them, then see if the Mac Mini can connect to the Wi-Fi.

for reference see > Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support

If you have disconnected or do not have any high speed devices or drives connected to the Mac Mini?

try the steps at > If your Mac doesn't connect to the Internet over Wi-Fi - Apple Support

A work around, if the computer is near the router then connect the two by ethernet then change the Network settings to Ethernet and see if you can connect. At least you can isolate the problem to the computer wi-fi.

Hello,

Let's try this, create a new user account on your Mac (you can delete it when we are done.) Once the new user account has been created then log out of your account and log in as the new user. If you are able to connect to Wi-Fi under the new user then there is a software conflict preventing Wi-Fi to connect under your primary user account. If it still does not work then most likely there is a hardware issue.

Set up users, guests, and groups on Mac - Apple Support