Depending on your enthusiasm for tinkering with external code / extension you might be able to setup something similar to what you want using the Roon Alarm Clock extension.
Another option, which will almost certainly provide you with the functionality you need, but will likely require more setup / work is Home Assistant running somewhere on your network (NAS, Roon Core, raspberry PI) with the Roon Integration installed. Then just setup an automation to trigger a playlist within Roon at a particular time.
Obviously you may just be asking for this as a feature in Roon itself, which is fair enough, just pointing out some ‘stop gap’ solutions you might want to try in the short term.