@Edward: It worked for me.
Using your commands, my netstat -ano shows:
I verified the PID(15080) from task manager as chrome.exe.
From the chrome session, use the URL chrome://version to display the launch command:
Command Line chrome.exe --remote-debugging-port=9223 --flag-switches-begin --flag-switches-end
Executable Path C:\Program Files (x86)\Google\Chrome\Application\75.0.3770.80\chrome.exe
to verify how chrome was started.
If chrome is already running, starting chrome.exe from the command line opens a new window on the existing chrome process
AND ignores any new --switches.