After a week learning about cold emails, I sent some out, and got a call with one guy who is leading a product team in my target market. Happy with that!
3 learnings from this:
mentoring is a good ask: it's a better message at my stage than sales. "startup mentoring" as a subject line is getting me 40% open rates.
senior beats junior: interestingly, so far people with a management title are more responsive than more junior team members. I can build a narrative for this, but it might just be random at my currently volume.
volume and exploration matters: even though my emails are probably not great quality, trying a few different target customers adding up to 25 emails has been enough to get a call.