The end-user chats are not presented to the agent even if they are available in Agent Workspace.
The issue in Dev was caused due to the 'Eligible at' value set in the Assignment Eligibility record.
The value is set to 30 min which means that only after 30 min the next set of agents will be eligible to take the assignments.
The OOB default value is 0 sec.
To resolve the issue, please revert back the Eligibility to 0 sec as per the OOB if not required/intended.