Spark already does what you're asking for:
https://helpspot.readdle.com/spark/index.php?pg=kb.page&id=1032
Copy/paste from the above link:
When the message is moved to Spam, the mail server will catch this info and mark all the following emails from that particular sender as Spammer.
Note: Some mail services (e.g. Google) use their own spam-detecting mechanism which operating principles may conflict with certain status User selects for emails
I think the key here is that it blocks "particular" sender. Spammers normally use randomly generated email address (and domain names) to avoid getting caught by filters.