new things hope this works

config/default/core.entity_form_display.block_content.hero_slide.default.yml

@@ -4,6 +4,7 @@ status: true
 dependencies:
   config:
     - block_content.type.hero_slide
+    - field.field.block_content.hero_slide.field_external_video
     - field.field.block_content.hero_slide.field_slide_image
     - field.field.block_content.hero_slide.field_slide_link
     - field.field.block_content.hero_slide.field_slide_text
@@ -16,16 +17,24 @@ targetEntityType: block_content
 bundle: hero_slide
 mode: default
 content:
+  field_external_video:
+    type: string_textfield
+    weight: 1
+    region: content
+    settings:
+      size: 60
+      placeholder: ''
+    third_party_settings: {  }
   field_slide_image:
     type: media_library_widget
-    weight: 26
+    weight: 2
     region: content
     settings:
       media_types: {  }
     third_party_settings: {  }
   field_slide_link:
     type: link_default
-    weight: 28
+    weight: 3
     region: content
     settings:
       placeholder_url: ''
@@ -33,18 +42,11 @@ content:
     third_party_settings: {  }
   field_slide_text:
     type: text_textarea
-    weight: 27
+    weight: 0
     region: content
     settings:
       rows: 5
       placeholder: ''
     third_party_settings: {  }
-  info:
-    type: string_textfield
-    weight: -5
-    region: content
-    settings:
-      size: 60
-      placeholder: ''
-    third_party_settings: {  }
-hidden: {  }
+hidden:
+  info: true

config/default/core.entity_view_display.block_content.hero_slide.default.yml

@@ -4,6 +4,7 @@ status: true
 dependencies:
   config:
     - block_content.type.hero_slide
+    - field.field.block_content.hero_slide.field_external_video
     - field.field.block_content.hero_slide.field_slide_image
     - field.field.block_content.hero_slide.field_slide_link
     - field.field.block_content.hero_slide.field_slide_text
@@ -15,6 +16,14 @@ targetEntityType: block_content
 bundle: hero_slide
 mode: default
 content:
+  field_external_video:
+    type: string
+    label: above
+    settings:
+      link_to_entity: false
+    third_party_settings: {  }
+    weight: 3
+    region: content
   field_slide_image:
     type: entity_reference_entity_view
     label: hidden

config/default/field.field.block_content.hero_slide.field_external_video.yml

@@ -0,0 +1,19 @@
+uuid: 6db81842-0403-4b92-bcea-b9e0f590c7b9
+langcode: en
+status: true
+dependencies:
+  config:
+    - block_content.type.hero_slide
+    - field.storage.block_content.field_external_video
+id: block_content.hero_slide.field_external_video
+field_name: field_external_video
+entity_type: block_content
+bundle: hero_slide
+label: 'External Video'
+description: 'An externally hosted video.'
+required: false
+translatable: false
+default_value: {  }
+default_value_callback: ''
+settings: {  }
+field_type: string

config/default/field.storage.block_content.field_external_video.yml

@@ -0,0 +1,21 @@
+uuid: 5c2255fb-5f8d-49ce-9206-d5348468cd7c
+langcode: en
+status: true
+dependencies:
+  module:
+    - block_content
+id: block_content.field_external_video
+field_name: field_external_video
+entity_type: block_content
+type: string
+settings:
+  max_length: 255
+  case_sensitive: false
+  is_ascii: false
+module: core
+locked: false
+cardinality: 1
+translatable: true
+indexes: {  }
+persist_with_no_fields: false
+custom_storage: false