Hi @hube2,
Thanks that explains the use of false, I have done some spring cleaning. Here is the working end result.
<?php $slide_datepicker = strtotime( get_sub_field('slide_datepicker', false, false) ); ?>
<time class="home__slide__date" datetime="<?php echo date('Y-m-d', $slide_datepicker); ?>"><?php echo date('d | m | Y', $slide_datepicker); ?></time>
Thanks for the support!