Hello,
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Based on our conversation, the data synchronization feature you want is something like a data center where the data is stored. Any app from different devices could be able to access or update the stored data and then other apps will get synced data. It's more like an online database.
Project Rome contains features like user activities, notifications, device relay, remote sessions, and nearby share. These features are not suitable for your requirement that used for syncing data.
So it is recommended to build your own server which host a database. When one app modified the data, send the update request to the database, then other apps on device will get the synced data when they query for it.
Thank you.
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