Time to talk about matrix.org and Element not Signal and definitely not Telegram...

Why not Telegram, it has by far the best UX of all chat apps.

Telegram (per default) does not have end-to-end encryption.

"Telegram is more secure than mass market messengers like WhatsApp and Line." https://telegram.org/faq#q-how-secure-is-telegram

The opposite is true - of all the major messengers, Telegram is the least secure.

It uses a homebrew encryption scheme and does not have E2E encryption (yes, you can enable E2E for individual chats, but nobody uses it because it breaks most features).

Not to mention the weird corporate structure, lack of transparency, failed crypto token launch, dishonest marketing...

A non-standardized, homebrew encryption scheme does not necessarily have to be worse than a standardized algorithm - even though it often is. But if implemented correctly and by someone who knows what they are doing, I'd trust a homebrew algo more than one which has been approved by the west's codebreakers for general use.

Do you have access to telegram source code, has audited it and/or know if they know what they're doing?

If yes, then you are connected to it somehow and is astroturfing. If not, then you're just astroturfing. By your last sentence it is clear