I have it working through a program called Chiaki which is much easier to set up than what you described. Please give it a try! You should be able to install it via desktop mode, using the Deck's built-in package manager.
I remember when DS9 came out. I thought and said, frequently, "This isn't Star Trek! Trek is supposed to be about people on a starship, going to new places! This crew isn't going anywhere, what's the point?"
It's a good thing that show runners didn't listen to "fans" like I used to be. Trek should always be free to try new things.
(No need to get into the specifics of the video. It's only 5 minutes, if you want to see factual errors and fat-shaming from some internet rando.)
If you must use them, get Qubes running on a cheap laptop and dedicate a Whonix VM to each "service". They won't know where you are or what sites you visit. Stay off of the "feed". Even then, assume they are acting against your interests.
Signal is the best intersection of genuine security and ease-of-use that I've ever seen. No choosing a server, no making an account. Just install the app, get a confirmation SMS, and now you can communicate with future-proof encryption and authentication right away.
For more technical people, who aren't going to be intimidated by things like making accounts and secure passwords and choosing servers, Signal is not the best. But when I need to communicate securely with non-technical people, it's a wonderful quick go-to solution.
"a crafted archive can escape its intended extraction directory and write files to other locations on the system. When chained, this can escalate to full code execution under the same privileges as the user"
To be clear, you want Tom's Hardware to downplay the severity of this situation?
It needs to be said. Because anonymity is only one part of privacy.
Security is another part - in messaging, this means that the message cannot be spied on in transit, and cannot be altered in transit.
Authenticity is another part - you need to know that the message came from who it claims to have come from, and not elsewhere.
Signal does not provide anonymity, basically. But it guarantees security and authenticity beyond doubt. And this is useful - you can exchange secure information with people using Signal, knowing that it's not being spied on or altered, knowing that only the person you intend to see the data can see it, and knowing that they know that you sent it.
But yeah, if you want to send messages anonymously, other services are necessary.
You literally don't understand how hashing works, got it. Please educate yourself on this topic. In short, "connecting your existing contacts" is ENTIRELY possible with hashed phone numbers; it's not even complicated or tricky. To claim otherwise, as you just did, is nothing but trumpeting your own ignorance.
As for deleting (and propagating deletion of) messages, this is most definitely NOT a matter of "just trust us". The client is open-source! We KNOW how it works. We KNOW that deletion propagates across devices when you tell it to. We KNOW that the service cannot see your unencrypted messages, and that the encrypted messages are made with AES so even quantum computers in the future can't decrypt them. This is incredibly far from "just trust us".
I have it working through a program called Chiaki which is much easier to set up than what you described. Please give it a try! You should be able to install it via desktop mode, using the Deck's built-in package manager.