Refer: https://www.howtogeek.com/197268/how-to-find-the-best-wi-fi-channel-for-your-router-on-any-operating-system/
- On your Mac [Alt] + Wifi Icon
- Open "Wireless Diagnostics"
- Ignore Wizard and open Window, choose Scan
- It will then rate your signals, and offer best 2.4 GHz and Best 5 Ghz channels
