The Problem Nobody Wants to Talk About (John Ozbay Interview)

Easy: they don't got Signal. You're likely waiting for Commodore Callback 8020.
The Problem Nobody Wants to Talk About (John Ozbay Interview)

There's SimpleX, there's Session... But people don't value privacy enough / they have no idea of the stakes.
You could also consider checking all your e-mails on HaveIBeenPwned. And follow the sites suggestions if there were some leaks. Three other things to consider: using services of disposable e-mail addresses; creating a fresh new e-mail for only trustworthy comms; considering using Signal/SimpleX/Session instead of e-mail (most e-mails are not E2EE!).
Phishing attacks are more common these days - just yesterday I got a banking phishing attempt through a call, which I promptly disconnected. If it's just a phishing attempt and you don't give in to it, you're most likely safe about them. But be specially careful, because some phishing attempts are smarter (through the use of AI and/or PII).
That already ended in my country (Portugal) and we have Chinese cams all over the place. It's a privacy nightmare come true.
I would chech for money that could have been stolen in your bank account (inform your bank if that's the case), change passwords (to 32 chars), but, otherwise, it could simply be phishing attempts.
"Dor de cotovelo"