Last time I tried Telegram to see what it is like, it did automatically broadcast to all my contacts, that I use Telegram, and as a consequence people thought they could message me there, even though I was only testing the app. Also it did require associating with my phone/SIM. Do you mean, that it does not publish your phone number to other people on Telegram?
I keep an eye on deltachat, hoping, that it might become a viable alternative to phone number associated chat solutions. Not sure how mature deltachat is already.
it should have asked you about that broadcasting. i am very sensitive about that so i am careful not to allow it.
deltachat is pretty mature for the features that it has. one nice one is that the autocrypt feature works with some regular email clients, so you can exchange encrypted deltachat messages with people who don't have a deltachat client.
it handles groups, image sharing, and integrates videochat with a configurable url (so you can use any video chat that can be opened through a webbrowser)
I keep an eye on deltachat, hoping, that it might become a viable alternative to phone number associated chat solutions. Not sure how mature deltachat is already.