Hi,
The Search Rooms request is used to find rooms containing a particular query string. Where the search query is used to reference room names or room descriptions. More information on this endpoint cn be found here https://developers.symphony.com/restapi/reference/search-rooms-v3

The endpoint you would need to use to query all the streams a user is a member of would be the following, https://developers.symphony.com/restapi/reference/list-user-streams

However this will only return results for the calling user (e.g your bot's Service Account). In order to call this endpoint on-behalf-of another user you will need to use OBO with the LIST_USER_STREAMS permission. More information on OBO can be found here https://docs.developers.symphony.com/building-extension-applications-on-symphony/app-authentication/obo-authentication