Graphene OS is amazing so far. I already consider it worth buying a new Pixel 4a for.
It's Android without Google, and it is signed, secure, private, and auto-updates.
Getting started with flashing new Android OSes takes effort, and I've been doing it on hard mode for a long time, but this is the simplest I have seen. It's not as simple as Signal, but... we're getting there.
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!