Could you please elaborate further on what exactly you want to block those email address typos from?
Would you like to prevent misspelled email addresses from being able to place orders on your store? If so, one solution is to use Shopify's Fraud Filter app. With this app, you can set up rules for each misspelled email, so that when the customer enters it within the checkout process, the order is automatically cancelled. See below:
You can read more about Fraud Filter in this Help Doc. Although it’s intended purpose is to help with blocking potentially fraudulent orders (I highly recommend installing for this intention too), it can also be useful to stop orders coming through from email addresses containing mistakes.
Let me know if this helps!
Q: "Could you please elaborate further on what exactly you want to block those email address typos from? "
A: Optimally, if I enter email@example.com instead of firstname.lastname@example.org while trying to order it would force a "woops, check your email" type message before the order is placed vs allowing the order to proceed in the first place. Would also be resolved if shopify had a checkout feature forcing the entry/validation of their email address twice to greatly reduce typos