is it possible to calculate and refer to estimated call wait time within connect without having contact lens?

Based on the experience you're trying to create, there are a number of solutions that can provide an estimated wait time to callers.

This blog provides a contact flow that will provide the estimated wait time based on the oldest call in queue.

This GitHub Solution provides a contact flow along with steps to deploy other AWS services, like AWS Lambda and Dynamo DB, to provide callers an estimated wait time based on the time of current calls waiting in queue.