Signal has been pretty throughly audited by data security experts. It’s as secure or more so than Telegram. It uses end to end encryption, same as Telegram. If you’re crossing the border, unlink your device, delete the app, and relink it later. Your account can’t be restore via SMS. I’m not sure what you mean by that. I’m sure my government can collect any data they want if they’re determined enough, but Signal is about as secure as it gets if you’re talking civilian digital communication.

Chats are only synchronized in Signal on actively linked devices. If you link a new device, your chat history will be completely blank at first.

If you’re on desktop, try using Claude 2 instead. I’ve had a much better experience so far. Much less repetitive in its responses. I like the way it breaks down answers with bullet points.