My attention to those emails is 20 emails * 10 seconds/email = 200 s / 60 s/min = 3.3 minutes of my time daily * 365 days = 20 hours per year!
What are my options for charging the sender for my attention?
Are there any crypto mining schemes for this, similar to javascript mining while visiting a webpage?
Then there are the spammers, who won't adopt your system, so you'll never receive their emails, which is great.
But the other category of sender is companies that you want to send you a receipt or some other automated message when you enter your email address in an online form. No one is going to rewrite their forms to pay more money to send you messages you asked for, so unfortunately you'll have to give up on receiving such messages.
Hmm, so I guess you could implement the system you want with just a whitelist, and you don't need any crypto mining scheme at all.