That command is wrong in several ways. You really need to understand more about how node.js works.
You have tried to use the master javascript file as the settings file (which is what destroyed your node-red install) and you have put the userDir in a location that only an admin and SYSTEM can access.
You don't need to specify settings as Node-RED will work that out, you can simply specify the userDir folder which should be in the selected users home folder somewhere. By default if you simply run node-red.cmd under a user id, it will put the userDir into c:\users\<userid>\.node-red. Just as if you ran it manually under your own logged in user.
I renamed the settings.js to node-red.js. Everything works with the Domain Admin account. I followed the documentation to share node-red between users.
But if i use a user of group users (local) it won't work. Sure, there are permissions missing. But wich permissions? (Running as Service is set)
Not really a brilliant idea I'm afraid. You should run node-red as a standard user if at all possible (and it should always be possible) to avoid issues like those seen in another recent thread on hacked servers.
If you leave it like that, you can expect your entire domain to be compromised pretty quickly.
I already pointed that out. It is because you put some files in the wrong place.