You can use the provided hook to modify the calendar view, enabling the display of time in the 24-hour format. However, your still have to utilize the backend settings, such as those accessible at https://i.imgur.com/QZ1TYNV.png, to adjust the formatting of the input field.
// Utilize the following filter to customize the time format for the calendar view.
add_filter('gf_awp_calendar_time_format', 'filter_gf_awp_calendar_time_format', 10, 2);
function filter_gf_awp_calendar_time_format($format, $form) {
// This modification exclusively impacts the time format within the Calendar view.
// Implement the moment.js format (refer to https://momentjs.com/docs/#/parsing/string-format/)
return 'HH:mm';
}
Code goes in function.php file of the active child theme (or active theme).