Monthly calendar not working

Hello,
we make a website for our client and we want on contact form of the date field to display a monthly calendar like in: https://kriesi.at/themes/enfold-restaurant-one-page/#reservations
We found from your documentation how to visualize it:
.ui-datepicker-calendar .ui-datepicker-week-end+.ui-datepicker-week-end a.ui-state-default, .ui-datepicker-calendar tr > td:first-child a.ui-state-default {
background-color: gold;
pointer-events: none !important;
}

But it turned out to be only visible when you logged in as an admin.
After searching in the forum, we found here (https://kriesi.at/support/topic/date-selection-contact-form/) a code for file function.php :

The script is being executed before jQuery loads, which is why it’s not working. I’ve added this code in the functions.php file to fix the issue temporarily
function ava_load_jquery_dep_script() {
wp_enqueue_script( ‘avia-datepicker-dummy’, get_template_directory_uri() . ‘/js/test.js’, array(‘jquery’), ‘1.0’ );

wp_add_inline_script( ‘avia-datepicker-dummy’, ‘jQuery(document).ready(function(){ jQuery(“.avia_datepicker”).datepicker({
beforeShow: function(input, inst) {
jQuery(“#ui-datepicker-div”).addClass(this.id);
inst.dpDiv.addClass(“avia-datepicker-div”);
},
showButtonPanel: true,
closeText: AviaDatepickerTranslation.closeText,
currentText: AviaDatepickerTranslation.currentText,
nextText: AviaDatepickerTranslation.nextText,
prevText: AviaDatepickerTranslation.prevText,
monthNames: AviaDatepickerTranslation.monthNames,
monthNamesShort: AviaDatepickerTranslation.monthNamesShort,
dayName: AviaDatepickerTranslation.dayNames,
dayNamesShort: AviaDatepickerTranslation.dayNamesShort,
dayNamesMin: AviaDatepickerTranslation.dayNamesMin,
dayNames: AviaDatepickerTranslation.dayNames,
dateFormat: AviaDatepickerTranslation.dateFormat,
firstDay: AviaDatepickerTranslation.firstDay,
isRTL: AviaDatepickerTranslation.isRTL,
changeMonth: true,
changeYear: true,
yearRange: “c-80:c+10”
}); });’ );
}
add_action( ‘wp_enqueue_scripts’, ‘ava_load_jquery_dep_script’, 10 );

but we put it in our site broke: the full slider stopped working, the menu refused, and more.

I appreciate the work of your team, the quick reaction and the exact directions.
Can you give me support?
Is it possible for a site visitor to choose only dates from today + 7 days?