With regular ROS (non CHR) it's more complicated, especially when running in VM. License is locked to things like drive manufacturer, name, serial number, etc.
If it was regular hardware drive, then these values would be inherently static and unchangeable. But with VM, every VM software may set these differently. Even if the actual image file for the disk remains the same, any change to these values will invalidate your license (machine ID will change).
I'm not familiar with Synology VM, so don't know which VM hypervisor/sw they use, but in general if you run the same on a different machine there is good chance the license will stay valid.
But if you move say from VirtualBox to VMware, there is pretty much zero chance that disks will be named same and license will not be valid.
At least with VM you can easily experiment and see what works...
...and if you have installed the CHR version instead of native ROS than none of this really matters