Suppress "Try the new cross-platform PowerShell https://aka.ms/pscore6"

Since Windows Terminal 1.0 is released, you can use it instead.In settings add a flag -NoLogo as shown below:

    "list": [  {    // Make changes here to the powershell.exe profile.    "guid": "{61c54bd-c2c6-5271-96e7-009a87ff44bf}",    "name": "Windows PowerShell",    "commandline": "powershell.exe -NoLogo",    "hidden": false  },

This message is part of the resource string embedded in Microsoft.PowerShell.ConsoleHost in the ManagedEntranceStrings.resources resource. The full message is

Copyright (C) Microsoft Corporation. All rights reserved.

Try the new cross-platform PowerShell https://aka.ms/pscore6

This is one string, not two, and there is no logic for picking a different banner.

Because the string is read as a resource, in theory you could create a new resource assembly and put it in C:\Windows\System32\WindowsPowerShell\v1.0\en-US. In practice you can't (even if you'd be willing to put new files in a system directory), because the main assembly is strong-named and installed in the GAC, which means you can't produce a satellite assembly that will load since you don't have the private key required for signing. It does, however, work -- I verified this by building such an assembly with delayed signing, but obviously that's not really a workable idea on a production system.

You can get rid of the copyright banner by starting powershell from running this in cmd:

Powershell.exe -NoLogo -NoExit

-NoExit is not necessary as @Albin said, and you could create a desktop shortcut/batch file from it.