If chrome.exe is launched, the usual behavior is for that new window and tab to join the same "instance" of Chrome running in the background. Specifically, they all share a networking and audio utility processes.
I would like to run a new instance of Chrome on Windows, that has its own separate set of utility processes. In other words, if you open the Chrome Task Manager, I shouldn't see tabs and processes from another instance.
Chromium flag --single-process is buggy and unsupported on Chrome, so that doesn't solve it, and I also don't strictly need a single process, just a separate set of processes.
The only one way to do this - is to use --user-data-dir switch and specify unique path to the user profile each time when you need separated browser process. This is for all chromium compatible browsers.