It is impossible to turn off the firewall notifications in Windows 10 Build 1903.
In January, I asked: "When is Microsoft going to fix the bug in Build 1809 that makes the firewall notifications IMPOSSIBLE to turn off?"
A. User replied with a an option to turn off all security notices in the registry file. How to Enable or Disable Notifications from Windows Security in Windows 10
I actually did that at that time. It worked. Then there were two other PCs in the house that had the same problem so I phoned up and a bunch of calls and back and forths later I was shown how to use a new Windows 10 account to reset errors in my current Windows 10 account. Except, I had significant trouble understanding the person and did not take good notes.
Now with Windows 10 Version 1903, all three PCs in the house are constantly notifying us that the firewall is off. All I did was experiment with the LAN settings and presto! Big Brother Microsoft was reminding me that I did not need one firewall, I needed two or three firewalls.
My guess is that Microsoft wants me to simultaneously run my router firewall, Windows Defender Firewall and the ESET NOD32 firewall because I was born with Fetal Alcohol Spectrum Disorder (FASD) and/or sniffed glue during the formative years.
So how do create an account and in the process restore the original accounts so I no longer get these constantly annoying messages?