I have a catch-all setup so any email sent to my domain, that is not a registered email, goes to a specific account. Then I just create a new email for each site. I also use Sieve rules (Fastmail) to process emails. Each email address for a specific site uses that site's dns name (amazon.com@foo.tld). If an email is sent to an address and the sender's domain doesn't match the left side of the "@" (with or without dots) than it's considered spam and I send myself an email saying someone likely sold my data.

Works great with Bitwarden's new username generation feature. I can create new accounts in a push of a button now.