Some problems with responsivness and hamburger menu

I switched off all plugins one by one, same problem appeared every time.
Child theme is done according WordPress.org descriptions (https://developer.wordpress.org/themes/advanced-topics/child-themes/).
My functions.php file is following:
<?php
function my_theme_enqueue_styles() {

$parent_style = ‘event-star-style’; // This is ‘evemt-star-style’ theme

wp_enqueue_style( $parent_style, get_template_directory_uri() . ‘/style.css’ );
wp_enqueue_style( ‘child-style’,
get_stylesheet_directory_uri() . ‘/style.css’,
array( $parent_style ),
wp_get_theme()->get(‘Version’)
);
}
add_action( ‘wp_enqueue_scripts’, ‘my_theme_enqueue_styles’ );
remove_filter(‘widget_text_content’, ‘wpautop’);
?>

I realised menu is working for 768px screen size if I remove that last part:
add_action( ‘wp_enqueue_scripts’, ‘my_theme_enqueue_styles’ );
remove_filter(‘widget_text_content’, ‘wpautop’);
But then all thedesign is messed up.

Hello!

I´m still struggling to get 1) slider image responsive mode to the normal size – it is currently tiny if looking in mobile, if changing from customizer “full” size, then it is enormous also in desktop size. How could I make it a bit bigger in mobile version if I selected from settings responsive mode?
2) Hamburger menu if looking on mobile does not open list of the links properly, it just shows it for half second

I have tried deactivate plugins, does not affect those issues.

Thank you, your advice regarding the mobile menu helped me to solve the issue!
Unfortunately, if I add a bigger image for the slider (I tried same then in event star demo has: 1280×610), it will display too high image on the desktop, all feature information section will be out of the viewport but mobile version is still a bit out of proportion and slider buttons are also out of the view partly. What would be the perfect dimension for the slider from theme perspective? And would it be possible to set a mobile version slider size in css?