Render node fields and labels in node template
The label is in the field definition, you have to add fieldDefinition before label:

{{ node.field_myfield.fieldDefinition.label }}


To explain this, node is the node object. Content is the render array of the fields, that are build as configured in the view mode. In node you find the raw values and definitions of all fields of the node. In content you only find those fields that are in included in the view mode and they are already formatted as configured in the view mode. You also find each of the fields as object in content, but you cannot be sure, that the field is there, because if someone later removes the field from the view mode, your code will get a null value.