Syncio does not have a native collection syncing feature but we can sync tags, which can be used to auto add products to collections. Tags are copied during the initial sync from the source store to the destination store. However, ongoing tag syncing requires the Pro Product Settings add-on to be enabled. Without this feature, tags on the destination store can be edited or removed without being overwritten by the source store.
If you have a mirrored set of collections set up on your Destination store, the tag sync can be used as a workaround to auto add products to the collections on your child store. To replicate the collection structure, you can add a unique tag to all products in a source collection, then search for that tag in the destination store’s Syncio app, select all results, and sync them, up to 100 products at a time.