I feel like there is some synology specific thing I am missing here. There’s some ideas on this thread Aeotec Z-wave stick Gen5 on Synology installation . Maybe you need to install an extra driver for the zstick? I’d be interested to hear @squirtbrnr thoughts on this with a successful zstick setup on synology.
It doesn’t appear you can use the synology gui here. The device option can’t be specified as an Environment variable.