I can see this isn’t a quick fix so just a note to add how to do this in case anyone wants to override this manually – specifically on the card view event listings.
Open plugins/eventprime-event-calendar-management/includes/templates/event_views/card.php
Go to line 101 or look for
<div class="em_event_start difl em_color em_wrap"><?php echo $start_time.' to '.$end_time; ?></div>
change this line to
<div class="em_event_start difl em_color em_wrap"><?php echo $start_time; ?></div>
This will only display the start time in the card view.
Similar changes can be made to other views if desired.
In future updates of this plugin the line numbers will no doubt change so please be aware this comment may not be relevant in the future. This was written for Version: 2.5.2.