I have been using for a while this open source plugin https://wordpress.org/plugins/advanced-bootstrap-carousel/ that uses a custom post type for which custom fields can be added but are not working. Right now adding slides is a pain, and requires me writing the css code along with html in the excerpt field of the plugin. What would it take to add support for custom fields to it? So that new slides can be easily customized without any code by end users. Examples of custom fields for a slider: alignment (center, left, right), background-color-text, font-sizes, font-colors, etc. I have tried as well doing the slider without any plugins without much progress though, I really wish I could code it myself
That plugin runs on shortcodes and you’d need to contact the plugin author. You can probably add custom fields to the post type it uses but you’d need to modify the output of the plugin and this would depend on if that plugin has filters that will let you modify the output and what modifications can be made with those filters.