Great article, Amar. I want to add 2 things:

• for a secure email you can use Protonmail (PM), also PM has a free/paid VPN servers across different countries. In my opinion, it's a good starter for people carrying about privacy.

• about WhatsApp. Actually, WhatsApp has implemented a Signal protocol for communication (source). I think, the main issue about WhatsApp is not about open chat messages, but about metadata owned by Facebook. Using only metadata you can identify and track people very efficiently. But, I totally agree with you that Signal is the best option.