WiFi Network Selection – When Did This Option Appear on macOS High Sierra?

Seems like no way to do this at the moment. Workaround:

The only solution seems to be to rename a spare access point to the SSID of the network you want to forget, connect to it with the iPhone, and choose the option to forget the network. This kludge seems like a lot of work and something that an average user probably doesn’t know how or want to do

via http://www.novainfosecportal.com/2010/07/08/forget-this-network-pretty-please/

MacBook Pro supports 802.11n wifi wireless networking. There are other wifi protocols like 802.11b and 802.11g. MacBook Pro is compatible with these (b and g) as well. Wifi issues prop up when your router supports other frequency and your laptop is trying to catch other frequency.

If your router supports 802.11b/g and compatible with n then it means some communication problem may arise between your wifi router and your laptop. Best thing that can be done here is to tell your router that it should send signal (broadcast) only on 802.11n.

Go to your wifi router settings (you need to connect your router to your laptop through cable for this. You can consult wifi router help book for this) and Fix channel as 11 (11 from 802.11 is called channel) and bandwidth as 150Mbps. n means it will run on 150Mbps. (generally b means 54 Mbps and g means 65 Mbps). Save your setting and you are hopefully ready to run without any hassle.

PS: You can do the same setting if your wifi is not visible or your MacBook Pro doesn't detect your home wifi.