Signal has improved a lot. I burnt a lot of the same thing, but it's finally sticking when I ask people to first install it within the last year or so.

Another vote for Telegram here. I tried to get at least the core group of family/friends on Signal or Wire and to their credit they tried but it never stuck. They loved Telegram so much that we now have the entire extended family/friends on it.

Interesting that you had such a different result with Telegram. I'd prefer to use Signal for privacy reasons, but like you I burnt a lot of social capital trying to get my extended family to use it!

It will be a hard sell for me to switch, that's for sure. I am already using Whatsapp for Western contacts, Kakaotalk for Korean contacts, and WeChat for China contacts. I don't have any Japan contacts currently, or else I'm sure I will have to install Line. I installed Signal on my laptop for one heavy-privacy-proponent friend, and had Telegram for a while for another friend's group business chat, but I never really used either.

Telegram has no end-to-end encryption for group chats at all.

And normal chats are not end-to-end encrypted by default. Are you using end-to-end encrypted chats with your contacts?

Another bonus of telegram (as compared to WhatsApp) is you can access the messages even when your phone run out of battery.

I had success at least moving my parents and sister to chat with me on Telegram. I was having weird issues with Telegram video call (very low sound on my parent's phones), so I still had to call them on Whatsapp. Also, didn't find any audio call option on Telegram, only video call.