Question about Icy Box Ib-3810u3

Theoretically, yes. The Synology devices are Linux computers and the ICY box is seen as USB hard drive(s) by the system. The drivers have long been available in common Linux distributions (e.g. Debian, Ubuntu). So this should work. However, you should not switch hard disks on/off during operation and the number of external hard disks may be limited by the software in NAS devices. But you can test this by connecting several USB sticks at the same time with a USB hub, for example. If you see all of them in the NAS, then this box should also work. It works similarly to a hub.