"Any simple way to sync all my contacts from the old iPhone 6 Plus to iPhone X without spending too much of my time?"
As for an iPhone fans just like you, are you wanting to buy a new iPhone X to replace your old iPhone? If so, you must be interested in how to
transfer contacts from iPhone to iPhone X directly, right? In fact, you need nothing but the Phone to Phone Transfer tool.
Phone to Phone Transfer can transfer photos, contacts, music, videos, calendars, call logs, messages, apps and app data for you. It supports iPhone, Android Phone, Blackberry, Nokia, Windows Phone perfectly. With it, you can copy data from one phone to another without any difficulty. Besides, you can backup and restore your iPhone data by using this tool.
1. Download, install and run the transfer program on your computer.
2. Connect your iPhones to computer with USB cables.
3. Select the data you wanted and transfer them from phone to phone.
Related:
Transfer Contacts from Android to iPhone X