How to hire for non-technical leadership roles?

My software consulting business has been trying in vain for two years now to hire someone to run sales. We've now hired and fired twice, and the rate at which we receive applications for the role is low.

Meanwhile, we've partnered with one of our clients to build a virtual events platform, and have a working product and a few guinea pig clients but the project really needs someone to take on a full-time sales role. Or even a co-founder-level CEO-type role.

For technical roles, I know where to look (personal network, meetups, conferences, slack groups, etc), and I don't feel like our hiring process is doing a great job of identifying competence.

I ask around in my network but my network is not at all sales-y. I put out job ads and get a slow trickle of uninspiring candidates that I don't feel I have a good assessment process for. I don't really know that many people in the sales/executive space, I don't know where the most competent people spend their time, and I don't know how to properly assess peoples' skills.

Is there a good place to find ambitious, hardworking people with strong people skills, good judgment, and enough technical ability to be able to communicate those topics effectively?

Has anyone here had success hiring for these kinds of roles, and can share their stories/processes?