MS SQL Server: How to sync multiple local database instances to single central instance?

I have let’s say 3 local database instances deployed at 3 different geographical locations around the world. I want to sync all these three local instances to one central instance deployed at yet another geographical location. I am looking for only one-way sync; from Local to Central. Finally, central instance will have data from all three local instances. Database structure of all the databases involved is exactly the same. Each local instance and the central instance are connected through internet; other necessary security is implemented and connectivity is available. If this is real-time, that will be great. But, if this causes some lag or delay, let's say an hour or so, that can be acceptable. I cannot use MS SQL Server's Replication feature as the connectivity will not be consistent. Connectivity may not be available for hours in some cases. As per my understanding and previous experience with Replication feature, this causes many problems and also need manual involvement to take the things on the track again. I have read [this](https://dba.stackexchange.com/q/77335/172299) . In general, Replication is not suitable in my scenario. Is there any other way to sync local and central instances?