Do the keywords used in the patent number query of listed companies take a company as the retrieval object or all patents of the group as the statistical object?

You are right to have this awareness, not only to check the company itself, but also to check all relevant companies within the listed group.

However, fuzzy search by name keywords is unreliable.

Correct, first look at the company's annual report and other materials, find out the names of all holding subsidiaries according to the annual report materials, and sometimes consider whether to join the company name of the controlling shareholder according to the shareholder information disclosed by the listed company.

Then look at all the company patents found and accurately query the company name one by one.