Hi,

I'd suggest you to create two categories: Private and Public, set their use permission to "Public" so that anyone can assign them to their events.

Then via the builder insert the category element to your event submission form:

I am afraid no, the event calendar is not visible in the tags like categories do but I will add your request in the upcoming release.

Are you familiar with JavaScript?

Anyway, this script will add the calendar as a tag.

Place the code in your child-theme functions.php file:

/**
 * Add calendar tag to event description
 */
add_action('wp_footer', function () {
?>
    <script type="text/javascript">
        window.stecOnEventDescriptionRender = function({
            data,
            element
        }) {
            const appendContainer = element.closest('.stec-content-tabs-content').querySelector('.stec-tags-list');
            const calendarName = data.calendar.title;
            const calendarColor = data.calendar.color;
            const html = `
                <stec-span class="calendar-tag" style="background-color: ${calendarColor}">
                    ${calendarName}
                </stec-span>
            `;
            const oldElement = appendContainer.querySelector('.calendar-tag');
            if (oldElement) {
                oldElement.remove();
            }
            appendContainer.innerHTML = html;
        }
    </script>
<?php
});