Whenever some app or service claims to respect your #privacy, check for two things:
1. Is it open-source on both client and server (if applicable) ?
2. Is the service itself decentralized in some way (federated, allows self-hosting etc.) ?
Now evaluate everything you use - iPhones, WhatsApp, Telegram, Signal, Gmail etc. using this checklist.
Try to find and use software/services which satisfy both of the above conditions.