I'm quite interested in a film called Total Trust that is due to come out later this month (Jan 2024) https://total-trust.org/

https://restoreprivacy.com/secure-encrypted-messaging-apps/session/#comments

This is pretty basic stuff for folk new to the concept of privacy: https://proton.me/blog/whatsapp-alternatives

https://bigbrotherwatch.org.uk/media/blog/