I have written a Blog post on this that could be a good read. You will find it here "https://everydaysitecore.home.blog/2020/04/29/change-droplist-field-source-item-value-using-sitecore-experience-editor/". This explains on how, when you need to use the droplist field, but still using sitecore experience editor, have a way to edit the value of the item pointed to my the droplist field rather than the droplist field value itself.