They all have iPhones and Google Android. Since all my calls and text messages are monitored on their phones, am I causing any additional harm to myself by using Google Messages on GrapheneOS? That way I could at least use RCS messaging.
delta chat. solves this problem as it uses the email protocol with pgp (when available), so from your end it’s a chat client and from their end it’s an email from you.
if they find it too annoying to reply by email they could just install the delta chat “email client”, too ;)