Some developers just write bad documentation. Some spend so much time in the weeds that when it comes time to write the documentation, they write a garbled string of words that tries to address all of the edge cases with not enough emphasis on the core usage. Others don't know how to express the concept of a feature in a simple and straightforward manner.
As a member of a Developer Experience team, I can confidently say that good documentation does not require a "certified" technical writer. Good API documentation just requires that another person, who has not worked on the feature, review the documentation in code review.
As a founder, it should be important to you that your business is providing the best possible value to your customers. If your business is providing an API, then you should cater to the developers who will be consuming that API as much as you are catering to the executives who will be signing the paperwork.