I was using Silence from F-Droid for a while back in the day because of these issues, but the lack of interop and needing to make everyone move again soured me on the whole thing. I would rather just get people on XMPP or Matrix and not use some sketchy phone-first app at all. For SMS I use Fossify Messages, which I think was a fork of QKSMS. I don't use SMS as primary or sensitive comms, only as needed. Same as email, basically, but less useful.
I really liked silence. I stopped using it when f-droid said the source code was no longer available. Fossify messages is the best replacement I've found.
(I dont bother with encrypted messenging apps. I prefer to assume that anything I do on my phone is doubleplus unprivate. If I want privacy, I head over to my computer.)
GrapheneOS is more well-roundedly private than any desktop OS.
Competition is Qubes but that has usability issues and does not have good hardware security.
The problem for me is writing on a mobile device is a terrible user experience.
When I'm at home I don't wanna use a virtual keyboard on a 6.3" (or 7.9 unfolded). I just want to use my triple monitor PC setup with a real keyboard and a wealth of display space.
Mobile is cool for on the go but a productivity killer.
I'm not about to trust a google branded device. Even if the Graphene folks are on the up and up, google sure as hell isn't.
That's not based in reality. Why would Google have a hardware backdoor when 99.9% of their users run their software giving them the data they want.
Google Pixels have no evidence of a hardware backdoor when a desktop is proven to be much less secure against remote and local exploitation.
It has been shown through leaks that Pixels running GrapheneOS are the most secure against Cellebrite in AFU. GrapheneOS was the first to implement a reboot timer feature which brings the device to BFU (much more secure) and then Android and iOS copied it (with longer, non-customizable duration).
You can inspect network traffic to see that GrapheneOS phones only connect to GrapheneOS-run services.
Here's a team member's thoughts: https://discuss.grapheneos.org/d/10150-not-your-average-why-...
But GrapheneOS relies on a proprietary, black-box security chip from Google... who pinky-promised to open-source it but never did, and that just doesn't sit well with me.
I think it's entirely possible that a compromised Titan module (whether such code ships with the device or is updated at a later point) could leak keys via some covert method, and possibly transmit via the baseband or through some other application/method where the OS is not really aware of what's going on.
The government only gets to use this once, and they probably won't use it on you.