Reset macOS Wireless Networking to Fix Slow WiFi

Purge the Network Configuration Files

/Library/Preferences/SystemConfiguration/

Rename the following files by adding a .bak extension

com.apple.airport.preferences.plist
com.apple.network.eapolclient.configuration.plist
com.apple.wifi.message-tracer.plist
NetworkInterfaces.plist
preferences.plist

Reset PRAM

Turn off your computer.

Turn on your computer and immediately press OPTION + COMMAND + P + R keys and hold for about 20 seconds and then release the keys.

Your Mac will restart.

Reset SMC

Turn on your computer and immediately press SHIFT + CONTROL + OPTION keys and hold for about 10 seconds and then release the keys.

Then, press the power button.