Divi theme – error message "www/wp-includes/l10n.php on line 69" since last wordpress update 5.5.3

Since the last update of wordpress 5.5.3, i’ve a 505 error. from the debug mode, i’ve this error.

configuration:

• wordpress 5.5.3
• divi theme
• OVH server provider
• PHP 7.2

Fatal error: Uncaught Error: Call to undefined function get_option()
in /home/website/www/wp-includes/l10n.php:69 Stack trace: #0
/home/website/www/wp-includes/l10n.php(137): get_locale() #1
/home/website/www/wp-includes/l10n.php(828): determine_locale() #2
/home/website/www/wp-includes/class-wp-fatal-error-handler.php(41):
load_default_textdomain() #3 [internal function]:
WP_Fatal_Error_Handler->handle() #4 {main} thrown in
/home/lecatamakp/www/wp-includes/l10n.php on line 69

some solutions, i did but don’t work.

• restore a backup from 5 days.
• disable plugins folder
• disable theme folder
• raise the the php_memory limit to 256MB
• change the PHP version
• compare an old backup (15days) with the actual app with diff -rq backup actual_app and i have not difference. there are absolutely the same.

the problem come from l10n.php

unction get_locale() {
global $locale, $wp_local_package;

if ( isset( $locale ) ) {
    /**
     * Filters the locale ID of the WordPress installation.
     *
     * @since 1.5.0
     *
     * @param string $locale The locale ID.
     */
    return apply_filters( 'locale', $locale );
}

if ( isset( $wp_local_package ) ) {
    $locale = $wp_local_package;
}

// WPLANG was defined in wp-config.
if ( defined( 'WPLANG' ) ) {
    $locale = WPLANG;
}

// If multisite, check options.
if ( is_multisite() ) {
    // Don't check blog option when installing.
    if ( wp_installing() ) {
        $ms_locale = get_site_option( 'WPLANG' );
    } else {
        $ms_locale = get_option( 'WPLANG' );
        if ( false === $ms_locale ) {
            $ms_locale = get_site_option( 'WPLANG' );
        }
    }

    if ( false !== $ms_locale ) {
        $locale = $ms_locale;
    }
} else {
    $db_locale = get_option( 'WPLANG' ); #--------------HERE IS THE PROBLEM----------------
    if ( false !== $db_locale ) {
        $locale = $db_locale;
    }
}

if ( empty( $locale ) ) {
    $locale = 'en_US';
}

/** This filter is documented in wp-includes/l10n.php */
return apply_filters( 'locale', $locale );

}

some user had a problem with this file l10n.php

https://wordpress.org/support/topic/l10n-php137-crashes-entrie-website/

i’ve change for a fresh file but don’t work.

I will try to install wordpress 5.5.1

Somebody have a workaround technic ? Many thanks