Here’s an idea from the radical left: If you’re going to ask job applicants to do a coding test, arrange for the tests to be judged blindly.
When musician’s unions became a thing in classical music, they insisted on blind auditions for orchestras. And behold, the number of women in prestigious orchestras shot up.
Before working on unconcious bias, eliminate its opportunity outright.
https://www.theguardian.com/women-in-leadership/2013/oct/14/blind-auditions-orchestras-gender-bias