My solution to spam emails is this: https://ahmedkaddoura.com/writing/hide-my-email

I create a unique iCloud Hide My Email anytime I need to give out an email. The issue here was I signed up for my 24 Hour Fitness membership in person at the gym where the cell service was bad and I couldn't get the WiFI to work, so I begrudgingly gave the guy my real email.

While I could have easily blocked their domain, I took it as a challenge to get the emails to stop.