I created a custom field 'Event date' for my custom post type 'Event'. I'm trying to display a date on the front end and want to change the display format of the date but it doesn't seem to work. Here is the code I tried:

<div class="single-post-event-meta">
                <p><?php 

                    $event_date = get_post_meta(get_the_ID(), '_event_post_date_value_key');
                    echo $event_date[0]->format('M');
                
                ?></p>
            </div>

Thanks for the help!