I embracing the path: "Sorry for the delay, I don't use this messaging app anymore because it has a lot of privacy/security issue, so I check it for new messages randomly. Feel free to contact me here <link> if you want a solid and trusty connection."

Slightly OT, why Signal?
If I'm not wrong it still asks to give out your phone number, and this doesn't seem a great start for a privacy focused platform.
Did you tried SimpleX Chat?