I can't speculate whether it would work. I suspect support thinks the radio issue would migrate over, whereas backups don't bring radio information over. Myself, I would try the backup method, it typically is a pretty safe option.
I would follow this guide first thing after migrating. Migrating a Z-Wave Network This will ensure you don't lose your devices or mess up and have the wrong device tied to the wrong automation/dashboard. The DNI is critical to change (make unique) on the Z-wave side of things when trying to use the backup method to change hubs.
From there, I think you need to do what this says. These are best practices. How to Build a Solid Z-Wave Mesh | Hubitat Documentation The last section Tips for designing your Z-Wave mesh are especially pertinent.
- When installing several devices, install Z-Wave mains powered repeaters first, beginning closest to the hub and working outward so other devices will be able to use them to reach the hub. Once the Z-Wave routers are installed, add your battery powered Z-Wave end devices.
