Seeking Tool for Webmaster Email Acquisition Based on Niche or DA

I'm currently on the hunt for a reliable tool or service that can assist me in obtaining emails for webmasters of specific websites. My primary criteria are based on niche or Domain Authority (DA). Like for example DA 30+ for tech niece.

I'm open to various solutions, be it a scraping tool, a paid list, or any other service. My main concerns are:

1. Scalability: I need a solution that can provide this data at scale, as I'll be working with a large number of websites.
2. Cost: While I'm willing to invest in a good tool, I'm also looking for something reasonably priced.

If anyone has experience with such tools or services, or if you've come across something that might fit the bill, I'd greatly appreciate your recommendations.

Thank you in advance for your insights and suggestions!