Spam messages intermittently appear in my Gmail Inbox that seem to be sent via relay through a salesforce server. For example, recent spam messages have been from addresses like "info@leadprostakealliancebuildguard.xyz via s1.y.mc.salesforce.com", "info@worthbeyondprogoverncloud.xyz via s1.y.mc.salesforce.com", "info@chiefdesignhubshieldselect.xyz via s1.y.mc.salesforce.com", and "info@investbasispremiummethodpilot.xyz via s1.y.mc.salesforce.com". I have zero past relationship with any of these solicitations. I think they are arriving merely because my email is publicly known.
As a fix, unsubscribing from them seems risky since it tells the sender that the email is active. Clicking links in the emails (as a way to investigate) seems downright perilous. And flagging the messages as spam for months has done nothing to abate their frequency.
Is there a way to filter, block, delete, or mark as spam all messages sent "via s1.y.mc.salesforce.com" or through a Salesforce server more broadly? Should I be contacting Salesforce and asking them to stop forwarding me this stuff? At this point, I am interested in any thoughtful suggestion, however creative.