Issues with the URL Hierarchy Structure

We’re facing a URL hierarchy issue in SEO stuff. Here is the explanation.

We’re going to add the main calendar on events listing page (parent page) on the URL: https://www.example.com/timely-event-listing-page/

so we expect that each events details page (child page) URLs should be
https://www.example.com/timely-event-listing-page/event-name-1/
https://www.example.com/timely-event-listing-page/event-name-2/
https://www.example.com/timely-event-listing-page/event-name-3/

Although, the actual events details page (child page) URLs are like this:
https://www.example.com/event/event-name-1/
https://www.example.com/event/event-name-2/
https://www.example.com/event/event-name-3/

The parent page is https://www.example.com/timely-event-listing-page/ and the child page is https://www.example.com/event/event-name-1/

each of the child page is under “/event/” which is not good hierarchy as per the SEO perspective. We want to maintain hierarchy, so the child page URL should contain parent page. Such as https://www.example.com/timely-event-listing-page/event-name-1/

Please suggest how to fix this issue.