It depends on the value of the custom field. If the value is a number, you can likely use a solution like this: https://wpshowposts.com/support/topic/sort-by-custom-field-value/#post-7803
I’m not sure about hiding events that have already happened. Perhaps the plugin you’re using can set them to “draft” once the date has passed?
You should be able to remove the read more button by leaving the read more option empty inside your list settings.
Let me know 🙂