So, I was told to not use Signal, so all that is left is Matrix. And I am not techy enough to have my own server and neither are my relatives, so Matrix.org is the only option
Signal is perfectly fine to use.
Most packages/installs of Signal contain proprietary code. I suggest Molly-FOSS instead.
Probably yes, it depends on your threat model.
If you are using E2EE on a matrix.org account then your message content, attachments (images) and most other traffic isn’t accessible to anyone but the people in the chat. However Matrix isn’t the most private option, it has a number of leaks such as reactions and chat topics (these are being worked on but aren’t close to happening).
For most people Matrix is a very private and secure option and the fact that it is federated is a huge plus. If you want something more secure you are probably looking at Signal (which you don’t want to use and isn’t federated) or Simplex Chat (which doesn’t have multi-device support).
Unfortunately even with E2EE, the admins of a homeserver can still impersonate you or take over your channel.
Of course you could run your own instance, or maybe none of this is part of your threat model, but I felt like bringing it up either way.
even with E2EE, the admins of a homeserver can still impersonate you
No, they cannot. Your homeserver admin could create an impostor login session on your account, but it would be pointless with E2EE, because it would be flagged with an obviously visible warning. You and all of your contacts would see that the impostor session was not verified as you (this typically shows up as a bright red icon on the impostor and another one on the room they’re in) and the impostor would be unable to read your communications.
simplex is good as an alternative
Yeah, sure. But Matrix is decentralized and federated. So you can pretty much join any instance and be able to talk with anyone on any instance. So why not select another instance
or maybe even self host one yourself?edit: didn’t read the text till the end
Why would Matrix be the only option? XMPP is significantly better. You can either sign up on a public server or pay a small sum to have your own private server for you and your family for example on https://snikket.org/ or I think https://jmp.chat/ also includes optionally a small server in the subscription.
