Explanation:
Box 1: Azure File Sync
Azure File Sync is fully supported on DFS Namespace servers, you can install the Azure File Sync agent on one or more DFS Namespace member servers to sync data between the server endpoints and the cloud endpoint.
Box 2: SMB over QUIC
SMB over QUIC offers an "SMB VPN" for telecommuters, mobile device users, and high security organizations. The server certificate creates a TLS 1.3-encrypted tunnel over the internet-friendly UDP port 443 instead of the legacy TCP port 445. All SMB traffic, including authentication and authorization within the tunnel is never exposed to the underlying network. SMB behaves normally within the QUIC tunnel, meaning the user experience doesn't change. SMB features like multichannel, signing, compression, continuous availability, directory leasing, and so on, work normally.
Reference:
https://learn.microsoft.com/en-us/windows-server/storage/file-server/smb-over-quic
https://learn.microsoft.com/en-us/azure/storage/file-sync/file-sync-planning#distributed-file- system-dfs