Yeah, there's line and whatsapp, also telegram on the apps side
If other social media who care about privacy that have a site.... uhhh, i can't think of anything else DX
If you're fine with email though, you can always use protonmail.
What do you want to use the app for exactly? :o As in for personal use, real life business, online chat, or?
And if you really care about privacy it said that most stuffs that's open source have a lot of privacy Also apps that don't connect to the internet and let you back up the data on your own