If the product itself is imported, but additional attributes are missing, the following steps might be helpful to resolve the issue:
Step 1. Ensure that the Entity Keys are added as prefixes to the columns' names in the import file.
In Magento's Import system, root entities and subentities refer to the hierarchical structure used to organize data during the import process. Root entities are the primary, top-level data objects that serve as the core of an import operation. Each import profile starts with a root entity, which defines the main type of data being handled, it contains such fields as SKU, entity_id, attribute_set_id. At the same time, Subentities are additional, related data points that extend or supplement the information provided by the root entity, for example: name, color, price. They provide more detailed information about a root entity and are imported as nested or associated records under the primary root entity. In order for the module to identify where the fields belong, entity keys for subentities are required. And, in the import profile we are providing the names of the entity keys for the entities, where they are required.
Here is an example for the root entity
And the subentity Product Attributes
It is important to make sure that these entity keys are added to the import file as prefixes in the column names.
It is possible to set unique custom entity keys for the fields, though, they still should be added to the import file as the prefixes in column names for proper validation and import of the data.
Step 2. Make sure that the columns' order in the CSV file corresponds to the order of fields in the import profile.
Make sure to keep the fields in your Excel or Sheets CSV file in the same order as they are arranged in the import profile, as the extension does not support mixing fields from different entities. For example, fields with the prefixes catalog_product_attribute must be grouped together, and all root entity fields should always be placed first. Only then will your import process run without errors.
Step 3. If you're using the 'Rows Merged into One' setting, the 'Merged Rows Data Delimiter' should differ to the 'Entity Key Delimiter', as is shown in the screenshots below:
Should the issue persist after the above-mentioned steps, don't hesitate to contact our Support Team.