Perhaps. However, the request is not a request issued to the DRC...

Perhaps. However, the request is not a request issued to the DRC as such. The request is the first formal step to commence arbitration under the ICSID Convention (i.e. a party commences arbitration by issuing a request for arbitration to the Secretary-General). I definitely agree with your suggestion that other steps had not worked though, given the gravity of bringing these proceedings.

The next step is screening and registration. There is some more info on this process on the ICSID website.