Conditional field display in node template
You wrote that you are using Twig conditions to selectively print fields, but they show up twice now. This most likely is, because your template still renders the entire content variable somewhere like {{ content }}.

You can easily avoid the fields being rendered twice by using the without Twig filter. Locate the {{ content }} part in your template and alter it to

{{ content|without('field_video', 'field_image') }}