Here is a Python script that you can use to extend current product categories by parent categories of these categories.

To use it you need to: 

• save this script into the extend_categories.py file
• download and install Python,
• install the pandas package by running this command in the terminal: pip install pandas
• export products from your store, rename the CSV file to products.csv, and place it in the same folder with an extend_categories.py file.
• run the script by the command in the terminal: python extend_categories.py

*In some cases, you may need to use pip3 and python3 instead of pip and python

It will add a column ExtendedCategory next to the Category column and save it into the modyfied_products.csv file.

Then you can check it and import it back to your store, choosing the ExtendedCategory column as a category column instead of the default Category column.

import pandas as pd
 
 
def extend_categories(categories: str):
    if categories:
        ext_categories = []
        for category_path in categories.split(';'):
            categories = category_path.split('/')
            for i in range(1, len(categories) + 1):
                path = '/'.join(categories[:i])
                if path not in ext_categories:
                    ext_categories.append(path)
 
        return ';'.join(ext_categories)
 
 
df = pd.read_csv("products.csv", encoding='utf-8', dtype=str)
ext_category = df['Category'].fillna('').map(extend_categories)
col_position = df.columns.get_loc('Category')
df.insert(col_position + 1, 'ExtendedCategory', ext_category)
 
df.to_csv("modified_products.csv", index=False, encoding='utf-8')
print('Done!')