I want to make tokens available for only 30 minutes to users. This is doable if we configure token lifetime policy but it's not working as I still get tokens valid for 1 hour.

Followed this suggested documentation

Step 2 : created the access token from the postman and validated the expiry time of the access token through

There were couple of policy Evalution restriction and prioritization rule for this policy refer to this documentation for more information on them.