I'm getting at the fact that most platforms do stupid shit like "this message might not be deleted if the receiver already saw it" like WhatsApp does and/or replacing messages with placeholders saying "this message was deleted". Telegram can be plain-text and can have a lot of issues but it guarantees that stuff is actually removed without trying to bullshit you like other do.
There's absolutely 0 guarantee that what you've "deleted" is deleted. On any platform really. But what you can rely on is the fact that the E2EE is there to make sure things are only readable by whoever the messages were intended for (barring being hacked and compromised keys etc). The message can say whatever it wants, doesn't mean a lot if you can't trust the source. Again, we're just talking about different threat models. With Telegram, it's not meant for secure and private communication. It has a different audience. And to push Telegram as a private or secure communication, you're actively doing the public a disservice.
If we assume that your privacy / security is broken (because it is) I might as well use the platform that provides the best desktop and mobile experience with fast syncs, ability to disable animations, have real desktop apps and not electron shit.
If you can't trust even open source technology that you can review and build yourself. And trust renowned cryptographers reviews of this technology.. then why are you in a privacy community telling people their experiences aren't true to what they're telling you?