Telegram group chats are not e2e encrypted, while Signal is notorious for being unreliable at actually delivering messages. Also, if you change your phone number the official Signal recommendation is to manually tell all your friends about the new number. WhatsApp just lets you do it.

I use both apps regularly but neither of them is perfect.

Yeah timely message delivery is a big problem for Signal. It doesn't happen often but when it does the delay can range from minutes to hours. A few years ago my wife and I failed to meet up as arranged and had a big yelling match until we looked at our phones half way through. The delay of some messages and not others led to almost exactly opposite beliefs about the electronic conversation we thought we had been having.

Out of interest what is your citation for Signal being nutritious or having messages going missing?

Anecdotally speaking, neither I or my friends that have been using Signal for years have every had any messages go missing, so I’m just interested as to why you might be experiencing this.

Every single person I know who uses Signal has complained about this. I'm glad Signal is reliable for you but that is not our experience.

Interesting! I just took a sample (be it small) of 5 people I speak with - none of them have noticed this as a problem.

I wonder if it’s something like geography based? By chance are your contacts mostly in the same country - if so which country?

Everyone I speak to on Signal is based in Australia, mostly in Melbourne but a few in Brisbane and Sydney.

In Telegram regular chats are not encrypted by default either. Only special “secret chats” are and they only can be established between mobile devices, not desktop.