how can I stop unwanted, offensive emails?

Depending on who your e-mail account is with ?

You might be able to Log into the Web Portal of your e-mail provider

Some and not all Providers may or may not offer >> Add e-mail addresses and or Domain names ( after the @ sign ie xx@icloud.com ) and Block the Sender or Domain

Domain Blocking will block ALL e-mail Addresses coming from ie xx@icoud.com so be careful using this method

This will not eliminate the offensive e-mails but may stop more from getting into your Inbox

I'm quite happy using spamcop.net to report them enough times until their ISP or Mail provider takes them down

You pay $15 to report a whole lot, not sure how many, but seems like about a year's worth... you get spam, you forward it to them, they'll track down the obfuscated senders & might take 2, 3, 4 times but the spammer will have to remove you from the spam list they bought... I actually think if there were about one million more people using spamcop.net that a spammers life would be nearly impossible to survive.

Of course if you have years or decades of being a nice spam receiver it could take a bit to make headway on it.

Last spam I got was on 06/23/2023

If you ever find a way, you’ll be rich. Blocking unwanted email is something many have been trying to do since email was invented.