You can use MultiWorld or Worlds plugin. https://poggit.pmmp.io/p/MultiWorld https://poggit.pmmp.io/p/Worlds There you have all the information about the commands and how to use them
And if you want to change the properties of the server like view distance or gamemode, etc... etc... you can use your server settings file. But with the plugins that i told you, you can change whatever you want.