How to prevent spam subscriber of your newsletter without captcha

I got a lot of spam newsletter signup from my website. Some website says I should use captcha. But I rather not using captcha both for user experience wise and design wise.

I use Genesis eNewsletter Plugin, Wordpress, and Sendy. I setup double-opt-in for signup. So good point is that people receive only a confirmation email. But still, more than 15 people receive an unexpected email from my domain. So I'm a bit paranoid that my domain will be in spam list in the future.

I want to solve this problem.🤔

Google's Invisible ReCAPTCHA…

Thank you! I will try it to see if it won't disturb people use VPNs, ad-blockers or/and privacy-focused browsers such as Brave or Vivaldi. I'm a user of all of these tools and all the time encounter google captcha. It's very much annoying and frustrating. That's why I wanted to go with captcha free-solution.