Built a review platform to hold online trading "gurus" accountable. Right now it's empty, how do you solve the cold-start issue?

I will not promote. Spent the last few months building a review platform for trading course sellers/mentorship programs, verified buyer reviews, proof of purchase required, no way for the creator to edit or delete a bad review.

Problem is obvious: it's empty right now, and an empty review platform doesn't signal trust or inspire community, but you need trust to get people to actually leave the first reviews. Classic chicken and egg.

Been doing direct outreach, DMing people who left reviews about these creators elsewhere, conversion is slow and doesn't scale well.

Anyone who's actually solved this exact problem (empty marketplace/platform, need first real content to build trust), what worked? Curious about sequencing too.