Then we can achieve this using Context Aware configuration and ParticipantStepChooser interface.
I have shared the approach with sample code in Re: AEM Workflow - Adobe Experience League Community - 449447
Instead of define the context aware configuration at site level , we can define the configuration at individual page level as we have only 4-5 pages.
Please note that personally I won't follow this approach incase of 30 pages.
In that case I will request business that we can have dedicated approver group(user group) and content authors can select individual approver[users are member of approver group] from page property and start the workflow.
We can read the approver or user name from page property and dynamically assign it an an approver using Dynamic Participant Step.