Hey Bryan,
Thanks for reaching out and for your interest in our plugins!
Custom fields are unfortunately not supported on the Community Events submission forms by default, with one exception: “Additional Fields” specifically created within Events Calendar Pro’s “Additional Fields” options.
These are essentially custom fields—but I just wanted to be clear that only fields created in the specific way described here are supported → https://theeventscalendar.com/knowledgebase/pro-additional-fields/
Check out those fields and see if they are robust enough to provide the features you need—if you need more specific control and want to use different kinds of fields, then unfortunately that would indeed require custom development. 🙁
I hope this information is clear and helps! Let me know.
Sincerely,
George