You’re assuming that the reason they don’t fill in your optional questions are lack of agency, when it is more likely they’d rather spend that time applying to

You’re assuming that the reason they don’t fill in your optional questions are lack of agency, when it is more likely they’d rather spend that time applying to more jobs. The early stages of the job market is called screening and is a wide net with low success rate. The incentives, especially with juniors, are to play a numbers game. If you are looking for culture fit, say that. And then have one such interview later in the process in a personal context. According to another commenter you’re asking for free labor (familiarizing themselves with your code and writing a design doc). If this is true, discussions of personal agency and creativity might be distracting from the real issues.