Yes, there is a super easy way to do this.

HelloElementor has made a default (blank) child theme available for free to use. So, all you need to do is head over to the Github repo for the child theme (managed by Elementor themselves) website and download the free child theme.

Upload the theme to your WordPress website. Activate the new HelloElementor Child theme. And, boom! You’re all set to add your custom function right in the new blank child theme.

More about the Hello Elementor Child theme:

The Hello Elementor Child theme is a starter blank child theme for the Hello Elementor WordPress theme. It resets the WordPress environment and prepares it for smooth operation with Elementor page builder. This theme includes support for WooCommerce and users are encouraged to use the styling capabilities in the Elementor plugin to customize their site’s appearance. The GPL license applies to this theme, just like it does with WordPress, so users can use it as a springboard to build their own sites using Elementor.