Did you follow these instructions ?
https://www.rme-audio.de/installation-guide.html
Especially this part ?
[...]
macOS - RME Interface is not recognized after successful installation?
Starting with the 10.13.2 update for macOS High Sierra, a new security feature requires users to approve new applications that interact with the kernel, a core part of the operating system. Find out how to authorize your Interface manually in System Preferences / 'Security and Privacy'. Help for High Sierra / Mojave Installation PDF.
[...]
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13