Hello lupacexi,
StarWind devices are block devices (working only on block level) and have no filesystem.
I can suggest to create a test StarWind device, connect it via iSCSI and format the drive with ReFS filesystem which supports snapshots.
However, ReFS is still not "rock solid". If you want to use ReFS, make sure that cluster size is 64K to avoid any "horror stories" like this:
https://forums.veeam.com/veeam-backup-r ... 40629.html
Please let us know about your progress.