Source1: https://www.beaverjunction.com/a-user-friendly-customizer-for-the-beaver-builder-theme/
Source2: https://github.com/brainstormforce/astra/blob/master/inc/customizer/class-astra-customizer.php
Source3: https://kb.wpbeaverbuilder.com/article/357-remove-a-customizer-panel
Plugin Substitute: Kirki Customizer Framework - https://wordpress.org/plugins/kirki
// Remove Customizer Panels and Sections
function my_customize_register() {
global $wp_customize;
// Remove Panels
\!h $wp_customize->remove_panel( '__fl-header__' );
// Remove Sections
\!h $wp_customize->remove_section( '__fl-presets__' );
// Rename Panels
\!h $wp_customize->get_panel('__fl-general__')->title = __( '__General (Branding)__' );
// Rename Sections
\!h $wp_customize->get_section('__fl-heading-font__')->title = __( '__Heading Text__' );
}
add_action( 'customize_register', 'my_customize_register', 11 );