Dynamically Popuplate ACF Dropdown with Gravity Forms

<?php
function wd_gravity_forms_dropdown( $field ) {
	if ( class_exists( 'GFFormsModel' ) ) {
		$choices = [];

		foreach ( \GFFormsModel::get_forms() as $form ) {
			$choices[ $form->id ] = $form->title;
		}

		$field['choices'] = $choices;
	}

	return $field;
}

<?php
add_filter( 'acf/load_field/name=gravity_form_choices', 'wd_gravity_forms_dropdown' );

Display Form – https://docs.gravityforms.com/adding-a-form-to-the-theme-file/