Petit test
Guess first, no penalty. Your keyword filter looks for "customer success". A strong candidate wrote "account management" for the same work. What happens?
A resume is a candidate's written work history. A keyword screen passes resumes that contain certain words and drops the rest. The same work goes by different names in different companies, industries and countries, so exact words are a weak signal.
The fix is structured criteria: a written list of the skills the job needs, with the different words people use for each one, scored the same way for every candidate.