You would benefit greatly then from switching to Debian for your many instances.
On Windows we do not support updating via command line, and even in Debian we would not recommend it as it is possible to force an update without the built-in checks of our system, and result in having to restore broken instances.
You can make good use of the 3CX Instance manager in this case, as well as save some resources on your PBX machines with Debian usually being a much lighter OS than Windows Server.
I'm not aware of any plans to add instance manager to Windows.
This is something exclusively available to the Debian version of 3CX, and relies on Debian-based frameworks not available for Windows. In addition, you cannot upgrade major versions of the PBX on Windows without uninstalling and reinstalling, so this is another point to consider in favor of Debian.
I'm afraid you will not be able to post it in the Ideas section as it is only available to Gold Partners and above. If a partner posts the idea of course, you can upvote it.