I use Wire and Signal. Honestly, there’s no point even comparing Signal with Telegram. The Signal client and the platform are abysmal — slow, unreliable (can’t say if the message will get delivered and when), generates device change notifications at random when nothing has changed, still can’t backup and restore chats on iOS, changing a device means jumping through hoops to join groups again, etc. In my usage, Signal is the antithesis of chat UX, though it has been improving very slowly over time.

Wire is a decent alternative since it also syncs chats across devices, but its clients are slow. Any chat with images will usually crawl when you scroll. The company also doesn’t care about free users (not that it should) and so it probably makes sense only for people who’re willing to pay.

WhatsApp shares metadata with Facebook. So it’s a complete non-starter.

Telegram has many features way beyond everything you mentioned. Telegram comes out ahead if you’re talking about non privacy related end user features. Even with WhatsApp, WhatsApp is limited to one mobile device. It’s desktop interface is weaker than Telegram’s and is a web interface. Needs syncing with mobile sometimes. Telegram has other nice things like the quick video 1 min memos.

Signal is so much more inferior for the end user outside of privacy there’s no reason to discuss it.

Insecure against what? These days, I'm more concerned about corporations data mining my private messages than government snooping, and I'm confident that Telegram accomplishes that. I'd use different messaging if I was concerned about state-level actors.

Much of picking a messaging system comes down to realistically assessing your threat model.