Hey @Mariasole,
Thanks for reaching out!
It unfortunately may not be possible to use the theme’s features on the events pages. I would recommend asking your theme developer about this, and seeing what their opinion is—they may be able to provide better assistance or add custom code for your theme to work as you hope.
One thing you can try, however, is to try changing the Events Template option for The Events Calendar and see if any particular page templates work better with the theme header features.
To do this, simply head to Events → Settings → Display in your site’s wp-admin. You will find the Events Template option here. Try out a different template option, save the changes, and then go back to the events page and try adding a custom theme header. See if anything improves. If not, return to the settings page, change the option to another template, and try again—and so on until you have tried all templates.
If this method still does not reveal a solution, then unfortunately there is not much else that can be done from the perspective of the calendar plugin itself, and I would recommend contacting the theme developer for further insight.
Let us know what you find!
Sincerely,
George