Try subscribing to any of them but from a new address, without signing up for Substack. Then, to replicate the evidence for the shadow profile, try unsubscribe

Try subscribing to any of them but from a new address, without signing up for Substack. Then, to replicate the evidence for the shadow profile, try unsubscribe from any of them from a signed-out session. The unsubscribe page may show a shadow profile with the new address then.