We have a customer comming from a Cisco Express and switching to PureCloud, on Cicso platform they have the possibility to record from a mobile phone and use the recording on a main number or queue. i cant see how this can be done within PureCloud.
Also, there are APIs and an Architect SDK to manage prompts in Architect. You can build your own integration to record prompts in any manner you choose outside of PureCloud and then use the APIs to upload new prompts.