Have you invested in Exchange 2013 and Hyper-V? Do you think you sill need to configure Pass-through (aka RDMs) Read this document from Microsoft to learn more about the best practices to have Exchange 2013 Databases running on VHDX.
No point of using legacy mode anymore. What does that give you as well? Using Veeam Backup and Replication, you can recover Exchange items in seconds using Veeam Explorer for Exchange or either you can start your machine from the backup in less than 2 minutes. Does that have sense? This is what Veeam calls Modern Data Protection.
See it in action here