Child theme implementation issues

There is most likely some issues about using get_template_directory_uri() or get_stylesheet_directory_uri().

According to WordPress Code reference:

get_template_directory_uri() function returns the URL to the root theme. If a child theme is
used and you want to return the URL to the current child theme, use
get_stylesheet_directory_uri() instead.

Also, it is noted that importing the parent CSS file is not a good practice anymore:

Note that the previous method was to import the parent theme
stylesheet using @import: this is no longer best practice, as it
increases the amount of time it takes style sheets to load. The
correct method of enqueuing the parent theme stylesheet is to add a
wp_enqueue_scripts action and use wp_enqueue_style() in your child
theme’s functions.php.

So, what you have to do is to enqueue the style by using the following code in your child theme’s functions.php file:

add_action( 'wp_enqueue_scripts', 'my_child_theme_styles' );
function my_child_theme_styles() {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );

}

And then enqueue your own CSS files if there is any.