@pete_x sorry I didn't get what you're after exactly. What's your goal ?
Telegram is a very practical app, with a lot of functionalities. For instance, on top of 1v1 (group is not possible, unlike Discord) audio/video chats, you can leave short audio/video recordings even when the recipient(s) is/are away from keyboard, to consult later.
"Secret chats" (to create, but just a click away, simple), are an option for improved security/privacy if that's a concern.
Also at all times, the history of communication can be cleared even on the side of the recipients if necessary.
A phone number is mandatory, just once at the registration, to receive code by SMS. But you could use a temporary disposable number eventually, either with a prepaid SIM or virtual numbers online, to separate it from your private one.
Personally I use this service
https://phitbone.com but there are many other solutions, including free ones (on the darknet - EM, you can buy guides on how to bypass SMS verification for $1, offering various solutions)
Tutorial
It requires payment by card or the crypto Zcoin (XZC), which could totally anonymise the transaction if you
mint the coins with the official wallet (it burns/discard the coins with their past transaction history to replace them with fresh new ones without a history, which you then send)
Often, I just don't bother and convert my Monero(/Bitcoin) to XZC (not minted but Monero prior is okay enough privacy) through
https://changenow.io
Anyway, past the registration (which shouldn't put you off)
it's possible to hide the Telegram phone number to other members of the network.
Just go to your settings : Privacy & Security > Phone number > Nobody
...AND do not add/save contacts in your contact lists (not necessary anyway)
Otherwise, it can be discussed but Telegram is respectful of your privacy in general. It's used by all sorts of criminals for this reason, including ISIS in the past & illegal trading. The owner/CEO has escaped from Russia to the UAE to stand up against the oppression & censorship of Putin & other governments repeatedly.
The app is much-loved among Russia's elites and top officials.
qz.com
Iran's Telegram ban, effective as of Monday, relates to concerns of the popular service being used to coordinate illegal activity.
www.cnbc.com