The guide has a mistake in the opening sentence: "No matter which Coinjoin implementation you use, at some point you are going to come across and have to deal with the change outputs they create."
This is no longer the case since the development of the WabiSabi coinjoin protocol. With WabiSabi, you can make your entire balance into private coins without leaving behind change: https://mempool.space/tx/d465033214fd2309dcce5a90c45fcaa788aa4394ee36debe07aad8d8a37907d2