Disable Escape Key (ESC) to Prevent Close Dialog
https://www.foxinfotech.in/2020/08/oracle-apex-disable-escape-key-to-prevent-close-dialog.html.
"Open your dialog page in Oracle Apex. Then right side in the property palette, scroll down to the Dialog section and add the following code to the Attribute property: closeOnEscape:false
Now save the changes and run its parent page to test and you will see, on Escape key press the dialog will not close."

Return a Value From a Modal Dialog
https://oracle-base.com/articles/misc/apex-tips-return-a-value-from-a-modal-dialog

Return the Dialog Page ID, to identify the Modal window that was closed
See the last comment on this page: https://community.oracle.com/tech/developers/discussion/4478903/dialog-closed-event-does-not-fire