Infuse Pro 6 and not syncing (Apple TV 4k)

Infuse 6 use iCloud to sync watched history between devices. Trakt will also work.

The prerequisites for using iCloud can be found here iCloud & Trakt Syncing – Firecore For using Trakt, you’ll just need to ensure you are logged into Trakt on all devices.

Also, Pro is available 2 ways: via in-app or via standalone paid app. The in-app option will include automatic updates to major releases. A bit more info can be found here. Infuse Pro: Purchases, Upgrades, and Family Sharing