Ask HN: How to obtain book endorsements when don't have industry connections?

My publisher is requesting endorsements for my book, but I'm not sure how to approach potential reviewers. The manuscript is complete and fully edited, but they're insisting that endorsements are essential for marketing.

I don't have any influencers or well-known figures in my personal network, so I'm considering cold outreach via email. For those who have published books or obtained endorsements before: what's the most effective approach?

Are cold emails to relevant experts actually viable, or are there better strategies I should consider? I'd appreciate any insights from the community about navigating this part of the publishing process.