Where to go with Microsoft Sync Framework?

Question

Microsoft

There is a project that implements synchronization of the central MSSQL database and a heap of SQL-Lite (mobile applications) using the MS Sync Framework.
MSSync itself has not been updated for a long time. What is now fashionable to use instead of it?
Requirements:
1. Work offline - mobile phones are synchronized at the request of the user
2. The ability to apply filters for each user (there is a lot of data, and it is utopian to transfer them for processing to the mobile phone in full).
3. The project was developed in C# (Xamarin), and its transfer to other technologies is a big question.
PS. I looked:
- Azure Sync - but as I understand it, it requires the central database to be in the Azure cloud.
- symmetricds.org - didn't see mobile device support
- pervasync - no iOS and Xamarin support