Unified platforms for this won't work since we need to yoink regular people from around the world. There's no one best major western platform either, they're all malicious live services that might switch up all their rules on you, take away the search bar, hide your friends' posts from you.

The solution is simple, don't count on these platforms to preserve your social links. Don't use Twitter DMs, whatsapp, or telegram, as soon as they want to get some work done, move people into XMPP. Move people on to to open platforms like this. Sure, they're less active, but you don't see random people walking through research departments off the street. They serve their purpose. People need to stop "leaving platforms", work on creating parallel resources. Change how you use them. Did everyone online really need to be able to see your whole life in the first place?