With one way or another, the need for better email validation will find the way to find you. You probably already checked out the documentation and see a lot of options that probably are a good fit for you.
The dns check by the way is a great choice if you want to keep a clean email marketing list.
After a little search I stopped in this post “How to Find or Validate an Email Address” that explains really well the logic behind email validation with a regex.
You are ready to use it in you Validation Form Requests or wherever else, just like any other rule.