Can I somehow exclude several dates and dates ranges in the datepicker field?

Hi,

For a range, you can use the JS options minDate and maxDate. Example

[
    'name'       => __( 'Date', 'your-text-domain' ),
    'id'         => $prefix . 'date_xabk9calx28',
    'type'       => 'date',
    'js_options' => [
        'minDate' => -5,
        'maxDate' => '+5D',
    ],
],

For some specific dates, Meta Box does not support doing that. You can follow this article to do by using the code https://codehasbug.com/javascript/disable-specific-date-in-jquery-datepicker/