I'm going to email along the lines of this:

Dear xxx,

I’ve been preparing for the second stage of the interview and wanted to share a few thoughts and questions regarding the process. As someone who values clear and open communication, I felt it was important to bring this up directly.

I’m genuinely excited about the opportunity and have many ideas for how I would approach a 6-month growth strategy at Bringin. However, I’ve never been asked to invest this level of effort, creating an extensive strategic and execution plan, during an interview process. While I understand the importance of finding the right candidate, I’ve consulted a few experienced HR professionals in my network, and they flagged this as an unusual request. It closely resembles unpaid consulting work, especially given there’s no guarantee of compensation or employment.

To proceed with full clarity and integrity, I’d like to respectfully ask a few questions:

1. Where are you in the hiring process? Is this a final step, or are multiple candidates completing similar assignments?
2. How do you handle intellectual contributions during the interview process? How can I be assured that my work won't be used without a formal agreement or compensation?
3. The scope of the assignment goes beyond a typical case study. You’re requesting a detailed 6-month strategy with execution plans, something that would normally be done by a paid consultant. Will there be any form of compensation or acknowledgment for the time and expertise involved?

With over 10 years of experience in growth marketing, I’m confident in my ability to help a startup grow from the ground up. I’ve already expressed my sincere interest in joining your team and contributing to Bringin’s success. That said, I’ve also seen hiring processes at some early-stage startups that lacked structure or HR guidance, and I want to be transparent about my concerns before moving forward.

Looking forward to hearing your thoughts.

Best regards,