Did you by chance restore a backup of Apps from your Fairphone 2 or somehow else install the same Apps in another way?
The Fairphone 2 Updater App doesn’t work on the Fairphone 3.
On the Fairphone 3 you simply go to Settings - System - Advanced - System update and hope it will offer you the update (until now updates were delivered via staged rollouts, so not everybody got updates immediately … and there are reports of trouble with certain mobile network providers, Orange in France and Vodafone as of now).