iOS 13 will all but eliminate robocalls, spam calls, and solicitors from ringing your phone.
This feature is called silence unknown callers, and is turned off by default. This feature will only ring your phone if the phone number is in your contacts, recent outgoing calls, or Siri suggestions. All other calls will go directly to voicemail.
This feature is enabled with iOS 13 in Settings find and select Phone, them scroll down until you see Silence Unknown Callers and slide the switch to on.
Apple has also included a Dark Mode feature in this upgrade. This is disabled by default, but you can turn it on in Settings, then Display and Brightness. You can also schedule Dark Mode here, so it automatically turns on at night and off in the morning, or leave it on all the time.