I think the point is not so mich whether you can trust Telegram or not (although I am shure you can't).

The issue with Telegram is, that (by default) it stores all your chats unencrypted on their servers. So they can just access every message of yours whenever they want. That is not only dangerous for privacy, but when their database gets hacked, there is a decent chance, that all of your chats are gonna be released. Also, if governments want access to Telegrams data, they are legally obligated to comply.

What you should look out for, when you want more privacy is:

1. Legit End-to-End encryption: That means, that all your messages are stored and transmitted encrypted and only you and the person, you are talking to have access to these keys. So even if the server of the messaging service, you use is malicious or the government forced the organisation, which is responsible for the messenger, it would be mathematically impossible to read any of your messages.

2. Open Source clients, that can be verified by security experts. End to End encryption doesn't mean much, when you can't verify what the service, you are using is doing with your private decryption keys. In other words: It isn't enough, if a company just says, they are doing encryption. The solution is Open Source clients, because that means, that everyone can see exactly what the apps are doing and can inspect the source code for backdoors or vulnerabilities. Usually, if a lot of people have been using them, you can be sure, that some experts have verified, that nothing fishy is going on.

If you want a simple suggestion, that has good encryption and is fully open source, but is still easy to use, I would suggest you go with Signal.