Error on setting up any theme

I’m trying to change the default theme on my localhost, but even when I try to activate one of the themes installed by default, such as twentyseventeen, I get the following error:

Fatal error: Uncaught ArgumentCountError: array_merge() does not accept unknown named parameters in C:\xampp\htdocs\wp\wp-includes\widgets.php:1265 Stack trace: #0 C:\xampp\htdocs\wp\wp-includes\widgets.php(1265): array_merge(wp_inactive_widgets: Array, blog-widget-area: Array, post-widget-area: Array, page-widget-area: Array, shop-widget-area: Array, side-widget-area: Array, basket-widget-area: Array, footer-widget-area: Array) #1 C:\xampp\htdocs\wp\wp-includes\class-wp-customize-widgets.php(279): retrieve_widgets(‘customize’) #2 C:\xampp\htdocs\wp\wp-includes\class-wp-hook.php(287): WP_Customize_Widgets->override_sidebars_widgets_for_theme_switch(”) #3 C:\xampp\htdocs\wp\wp-includes\class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array) #4 C:\xampp\htdocs\wp\wp-includes\plugin.php(478): WP_Hook->do_action(Array) #5 C:\xampp\htdocs\wp\wp-settings.php(568): do_action(‘wp_loaded’) #6 C:\xampp\htdocs\wp\wp-config.php(90): require_once(‘C:\\xampp\\htdocs…’) #7 C:\xampp\htdocs\wp\wp-load.php(37): require_once(‘C:\\xampp\\htdocs…’) #8 C:\xampp\htdocs\wp\wp-admin\admin.php(34): require_once(‘C:\\xampp\\htdocs…’) #9 C:\xampp\htdocs\wp\wp-admin\customize.php(13): require_once(‘C:\\xampp\\htdocs…’) #10 {main} thrown in C:\xampp\htdocs\wp\wp-includes\widgets.php on line 1265

My xampp version is the latest one with PHP 8, and MariaDB.
Also, the WordPress I have is the latest version. I just downloaded it yesterday.

Edit:
I found out that there are several other errors on my site. For example, even after setting the home page from the dashboard, I still see Page Not Found. This also applies to another page I manually created.
On that very page I also see:
Warning: get_comment(): Argument #1 ($comment) must be passed by reference, value given in C:\xampp\htdocs\wp\wp-includes\class-wp-comment-query.php on line 484

• This topic was modified 3 years, 11 months ago by ca0c.
• This topic was modified 3 years, 11 months ago by ca0c.