Your plan to book longer sessions to minimise the percentage of ground time, and less useful time in transit to the training area is a good idea. I still think 0.3 ground time per flight is excessive at an airfield where there are no traffic delays. 0.2 should be plenty.
But, that issue aside, if you are not getting clear briefings and constructive debriefings, you certainly need to discuss it with the operator.
Learning to fly is unusual in business in that the customer is not always right (the instructor should be), but your money does give you some say in how you expect training sessions to be conducted. If the school has its instructors on 30 minute turnarounds, that’s a business model to make money without delivering quality.
Find an operator who devotes more time to each student.