No encryption, no peace of mind

People often bring this up as an issue with Telegram, however if you want large casual groupchats with easy syncing and access to bots this is how it has to be. The moment 3rd party bots enter the equation end to end encryption has a hole in it. Large numbers of people also cause the encryption to be moot if one of the people you invite in are saving their logs and such.

Also while the default chats arent end to end encrypted, they are still encrypted. This isnt as as strong but it means your ISP isnt casually able to sniff around whatever youre sending.

Seems like crypto people do not like telegram because they rolled their own crypto. Often kind of a red flag. Counter is that I am not sure there is a known issue with it beyond the standard complaints.

Not sure why you would choose Telegram over Signal. The one thing I do not like about signal is your phone number is your ID though.

Telegram may disclose IP addresses and phone numbers to relevant authorities if you are a member of a confirmed terrorist organisation.

Matrix does exist. It has another level of "barrier for entry" but its probably the least worst option excluding network effect.

If installed on your phone it will keep syncing your contacts, which is what most parties are interested in anyway (should be the main reason to uninstall). Your options are IRC, xmpp and matrix (element) if self hosted (matrix is somewhat in question about its origins).