It sounds like your RAID device only supports the USB protocol and not the Thunderbolt protocol. When connecting devices to a computer, it is very important to know the protocol being used by the device over the USB-C ports. Unlike your Mac where the USB-C ports support both USB & Thunderbolt protocols (for example: some of the Mac Studio ports do not support both), most external USB-C devices will only support one of the protocols.
A device should ideally mark the USB-C port with the protocol supported. A Thunderbolt port should have a lightning bolt icon, whereas a USB port should show a trident symbol. If there is no symbol next to the USB-C port, then most likely it only supports the USB protocol. If in doubt, check the product documentation and user manual to confirm.
You can only connect USB devices to another port which supports the USB protocol. And you can only connect a Thunderbolt device to another port which supports the Thunderbolt protocol. You cannot convert between the two protocols, at least not with any simple inexpensive adapters. Keep this in mind when connecting USB3/4 or Thunderbolt 3/4 devices to older Macs only supporting the older legacy ports (USB3 A/B, or Thunderbolt 1/2 ports).
FYI, "USB-C" is only a connector designation & type.