Sudden Barrage of Emails!!!!

You need to --> Identify and filter junk mail in iCloud - Apple Support

Unless you actually signed up for them or those accounts you can be sure they are just trying to get your information. I’d adjust your spam / junk email filter as already suggested. Sadly these things get sent out by the millions and once a junk mailer knows the account is active, On one of my accounts they just change the domain by one character and I get another batch of them. If you haven’t already I’d suggest making a junk account and when a store or site requires an address give them that one. I open mine about once a month, select all and delete.

Best of luck