WP_Query on diff post_types with custom conditions

post_types.php

<?php

/**
 * Event layout
 */

get_header();

$description = get_the_archive_description();
?>

<header class="page-header alignwide">
    <?php
    require get_stylesheet_directory() . '/template-parts/header/event-header.php';
    ?>
</header><!-- .page-header -->
<div class="event-archives mx-auto">
    <div class="entries m-2">
        <?php

        $currentDate = date('Y-m-t');

        $args = array(
            'post_type' => 'event',
            'post_status' => 'publish',
            'order' => 'DESC',
            'posts_per_page'    => 10,
            'meta_query' => array(
                array(
                    'key' => '_event_start_date',
                    'value' => $currentDate,
                    'compare' => '>='
                )
            )
        );
        $loop = new WP_Query($args); ?>

        <?php if ($loop->have_posts()) : ?>
            <?php
            while ($loop->have_posts()) : $loop->the_post(); ?>
                <div class="event-entry pt-10">
                    <?php get_template_part('inc/archive/event-archive', 'card'); ?>
                </div>
            <?php endwhile; ?>
        <?php else : ?>
            <h2 class="p-4 text-center"><?php echo __('No upcoming events', 'accilium_theme'); ?></h2>
        <?php endif; ?>
    </div>

    <!-- archive list ends here -->
    <?php

    $events_q = new WP_Query(
        array(
            'post_type' => 'event',
            'fields' => 'ids',
            'nopaging' => true,
            'order' => 'DESC',
            'post_status' => 'publish',
            'meta_query' => array(
                array(
                    'key' => '_event_start_date',
                    'value' => $currentDate,
                    'compare' => '<',
                    'type' => 'DATE'
                )
            )
        )
    );
    // var_dump($events_q);
    $posts_q = new WP_Query(
        array(
            'post_type' => 'post',
            'fields' => 'ids',
            'nopaging' => true,
            'order' => 'DESC',
            'post_type'   => 'post',
            'cat' => array(89, 36),
            'order' => 'DESC'
        )
    );


    // Sum up all IDs

    $event_items = $events_q->get_posts();
    $post_items = $posts_q->get_posts();
    $ids = array_merge($event_items, $post_items);

    $wp_query = new WP_Query(
        array(
            'post_type' => array('event', 'post'),
            'post__in' => $ids,
            'order' => 'DESC',
            'posts_per_page' => 12
        )
    );
    ?>
    <h2 class="p-4 text-center"><?php echo __('PAST EVENTS', 'accilium_theme'); ?></h2>
    <?php
    // The Loop
    if ($wp_query->have_posts()) : ?>
        <div class="slick-wrapper relative">
            <div id="posts-slider" class="slick-slider">
                <?php while ($wp_query->have_posts()) : ?>
                    <?php $wp_query->the_post(); ?>
                    <article>
                        <div class="slide-item">
                            <a href="<?php the_permalink(); ?>">
                                <figure class="slide-img">
                                    <?php
                                    if (has_post_thumbnail($post->ID)) {
                                        echo the_post_thumbnail('slider-thumb');
                                    } else {
                                        echo '<img src="' . get_stylesheet_directory_uri() . '/assets/img/acc_280-200.png"/>';
                                    }
                                    ?>
                                </figure>
                                <?php
                                $event_date = get_post_meta(get_the_ID(), '_event_start_date', true);
                                // Check if the event_date field has a value.
                                if (!empty($event_date)) : ?>
                                    <p class="slide-date"><?php echo date_i18n(get_option('date_format'), strtotime($event_date)); ?></p>
                                <?php else : ?>
                                    <p class="slide-date"><?php echo get_the_date(); ?></p>
                                <?php endif; ?>
                                <p class="slide-title"><?php the_title(); ?></p>
                            </a>
                        </div>
                    </article>
                <?php endwhile; ?>
            </div>
            <div class="slick-slider-dots"></div>
        </div>
        <?php wp_reset_postdata(); ?>
    <?php endif; ?>

</div>

<?php get_footer(); ?>