timezones for calendar

Hi,

I need to make timezone filter for your calendar. But I have some problem.
I added arguments via inline.js file:

//———–

var wpfc_loaded = false;
var wpfc_counts = {};
jQuery(document).ready( function($){
	const urlParams = new URLSearchParams(window.location.search);

	let fullcalendar_args = {
		timeZone: urlParams.get('time-zone-selector'),
		timeFormat: WPFC.timeFormat,
		defaultView: WPFC.defaultView,
		weekends: WPFC.weekends,
		header: {
			left: WPFC.header.left,
			center: WPFC.header.center,
			right: WPFC.header.right
		},
		month: WPFC.month,
		year: WPFC.year,
		firstDay: WPFC.firstDay,
		editable: false,
		eventSources: [{
				url : WPFC.ajaxurl,
				data : WPFC.data,
				ignoreTimezone: true,
				allDayDefault: false
		}],
	    eventRender: function(event, element) {
			if( event.post_id > 0 && WPFC.wpfc_qtips == 1 ){
				var event_data = { action : 'wpfc_qtip_content', post_id : event.post_id, event_id:event.event_id };
				var tippy_vars = {
					theme : WPFC.tippy_theme,
					placement : WPFC.tippy_placement,
					content : WPFC.tippy_loading,
				}
				$(document).trigger('wpfc_tippy_vars', [tippy_vars]);
				$.extend(tippy_vars, {
					onCreate( instance ){
						instance._loaded = false;
					},
					onShow( instance ){
						if( !instance._loaded ) {
							instance._loaded = true;
							$.get(WPFC.ajaxurl, event_data, function (content) {
								if( content !== '' ){
									var el = $('<div></div>').html(content);
									instance.setContent(el[0]);
								}else{
									instance.setContent('...');
									instance.hide();
									instance.destroy();
								}
							});
						}
					}
				});
				tippy(element[0], tippy_vars);
			}
	    },
		loading: function(bool) {
			if (bool) {
				$(this).parent().find('.wpfc-loading').show();
			}else {
				$(this).parent().find('.wpfc-loading').hide();
			}
		},
		viewRender: function(view, element) {
			if( !wpfc_loaded ){
				var container = $(element).parents('.wpfc-calendar-wrapper');
				container.find('.fc-toolbar').after(container.next('.wpfc-calendar-search').show());
				//catchall selectmenu handle
			    $.widget( "custom.wpfc_selectmenu", $.ui.selectmenu, {
			        _renderItem: function( ul, item ) {
			        	var li = $( "<li>", { html: '<div>'+item.label.replace(/#([a-zA-Z0-9]{3}[a-zA-Z0-9]{3}?) - /g, '<span class="wpfc-cat-icon" style="background-color:#$1"></span>')+'</div>' } );
			        	if ( item.disabled ) {
			        		li.addClass( "ui-state-disabled" );
			        	}
			        	return li.appendTo( ul );
			        }
			    });
				$('select.wpfc-taxonomy').wpfc_selectmenu({
					format: function(text){
						//replace the color hexes with color boxes
						return text.replace(/#([a-zA-Z0-9]{3}[a-zA-Z0-9]{3}?) - /g, '<span class="wpfc-cat-icon" style="background-color:#$1"></span>');
					},
					select: function( event, ui ){
						var calendar = $('.wpfc-calendar');
						menu_name = $(this).attr('name');
						$( '#' + menu_name + '-button .ui-selectmenu-text' ).html( ui.item.label.replace(/#([a-zA-Z0-9]{3}[a-zA-Z0-9]{3}?) - /g, '<span class="wpfc-cat-icon" style="background-color:#$1"></span>') );
						WPFC.data[menu_name] = ui.item.value;
						calendar.fullCalendar('removeEventSource', WPFC.ajaxurl);
						calendar.fullCalendar('addEventSource', {url : WPFC.ajaxurl, allDayDefault:false, ignoreTimezone: true, data : WPFC.data});
					}
				})
			}
			wpfc_loaded = true;
	    }
	};
	if( WPFC.wpfc_theme ){
		$.extend(fullcalendar_args, {theme: WPFC.wpfc_theme});
	}
	$(document).trigger('wpfc_fullcalendar_args', [fullcalendar_args]);
	$('.wpfc-calendar').first().fullCalendar(fullcalendar_args);
});

All regions I am getting via php:
DateTimeZone::listIdentifiers();
So all strings are correct. But nothing changed with schedule. All events are in same positions.