I just jumped on the final "sender" as likely being the "from" in all of the spam, making a Mail.app rule easy to set up. I received an unrelated spam email today and did just that. Setting up a rule to block it was really easy. In fact, after I clicked Apply Now, I got the satisfaction of seeing the offending message evaporate. 
Jon
macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365
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