To call a PowerShell (PS) script from another PowerShell script and have it run in a second terminal window without exiting, you can use a script similar to:
Start-Process PowerShell.exe -ArgumentList "-noexit", "-command .\local_path\start_server.ps1"

When developing in Visual Studio Code, I

I've really enjoyed working in PowerShell, but having never really worked with the Command Line or shell scripting before, there's a lot of little tips and tricks out there that I wish had been compiled into a quick start guide.

One of those examples is how a command would work