Hi @Sumit Jain
Enabling sessions is a control plane operation. You can use the REST API to receive messages from the queue/subscription that may not be a session, but you can't receive a session itself. Yes, your understanding is correct that it is a limitation that the Session receivers are not supported in REST Client.
I have got an update from my team that this feature to support sessions receivers in REST API is currently not on the roadmap of the Product team. The only way would be switching to AMQP or AMQP over WebSockets using one of our supported SDKs for retrieving messages from sessions.
To learn more about the session you can refer to this document.