Just for a family and friends I’d go for xmpp. Matrix is still an enormous greavy piece of software, hard to self host if you don’t want to pay for a gigantic server just for it. Also the UI is more like gamer/company chat (discord, slack…), what may not be what your family expect, coming from whatsapp, telegram, or plain sms. In the contrary xmpp is very light and nowadays a lot of tutorial exists on how to configure it, even with voice/video. Plus mobile apps like conversation match the habbits of other messengers.

I’d love to have a link to the wallpaper :)