Thanks so much for reaching out!
Changing the events permalink structure is not something possible without doing some custom coding.
And, as you will find in the following article it is a best practice to use “Post Name” option > https://theeventscalendar.com/knowledgebase/permalinks-best-practices/
If this functionality is a requirement for your intended project, I’d suggest that a third-party developer would be the best way to make this feature happen on a short timeline. ? We maintain a list of developers who work with our plugins on our Knowledgebase here:
https://theeventscalendar.com/knowledgebase/find-a-customizer/
If this is something that is really necessary for your site, you can try to incorporate a third-party plugin, like Custom Permalinks, though I cannot make any guarantees about compatibility.
Let me know if you have any other questions on this topic!
Thanks,
Jaime