Yes the RMM is not supported on AEM as a cloud service. Even I am looking for alternative options but haven't figured out yet. I guess the reason this or any such custom feature will not work on AEM as a cloud service because in cloud the dispatcher and publisher instances are scaled up and down automatically. And redirect rules config will be lost anytime a new dispatcher is added on scale out event. So the only option left is either you manage your redirects on CDN or you manage them via dispatcher code.