Or, bear with me, just send a massive amount of spam mails to leaked mailing lists. Maybe 1 in a million reacts and you scam them (cfr all the “Nigerian prince” scams.
A looooot less work because the victim’s will contact you themselves. No need to go and “compare which phones show up together and them figure out why they were together and then figure out if it was an affair or not and then contact them in the hopes they care enough to pay ransom”
‘People have no idea’: How smart devices spy on us and reveal information about our homes (english.elpais.com)