FullCalendar Events Not Displayed

I have been struggling with FullCalendar since we upgraded to WP 5.8. It is not displaying any events and when it does, it displays them on the day/time I entered them into the calendar and not when the event actually is. I found the following errors:

jquery.fancybox.pack.js?ver=5.8:2 Uncaught TypeError: Cannot read property ‘msie’ of undefined
at jquery.fancybox.pack.js?ver=5.8:2
at jquery.fancybox.pack.js?ver=5.8:34

Uncaught TypeError: $(...).fancybox is not a function
    at general.js?ver=5.8:820
    at HTMLDocument.<anonymous> (general.js?ver=5.8:849)
    at e (jquery.min.js?ver=3.6.0:2)
    at t (jquery.min.js?ver=3.6.0:2)

And this warning:

jquery.min.js?ver=3.6.0:2 jQuery.Deferred exception: $(...).fancybox is not a function TypeError: $(...).fancybox is not a function
    at https://www.scc-arts.org/wp-content/themes/blessing/js/general.js?ver=5.8:820:57
    at HTMLDocument.<anonymous> (https://www.scc-arts.org/wp-content/themes/blessing/js/general.js?ver=5.8:849:4)
    at e (https://www.scc-arts.org/wp-includes/js/jquery/jquery.min.js?ver=3.6.0:2:30038)
    at t (https://www.scc-arts.org/wp-includes/js/jquery/jquery.min.js?ver=3.6.0:2:30340) undefined

I inherited this account. The person before me hadn’t upgraded nor backed up the site since 2018. I backed up the site twice. Of course, one was corrupt and the other did not back up the calendar. I have since backed it up a third time. Note: I do front-end web work; I do not write code. Please dumb everything down for me. I will not be offended. A friend who does back-end web work was helping but had a family emergency so I’m stuck.

The page I need help with: [log in to see the link]