I get a lot of what you're saying, but I think you're conflating signal-to-noise with disappearance of the old weird web. It's still there, there's just a lot more other stuff out there too.
For the most part I agree with what you say about big tech and their dominance, but you don't have to use their products for the most part. The web standards are the big problem in that context.
Genuine question - why do you feel you have to use TikTok?
The problem is that these platforms have, in a very meaningful sense, taken the place of communications infrastructure. The bulk of us use Messenger or iMessage/FaceTime or some other over-the-top service for things we would have otherwise texted, or sent over email, or called someone about using a dialer, and that contributes to the vendor lock-in that they have. It's the new IRC, or AIM, but with an even wider capability gap and a userbase billions deep.
Even RCS doesn't solve this, because they're still a technically inferior spec - they don't support E2EE, and they still depend on phone numbers, with the terrible user experiences of arbitrary last-century identifiers and the phone companies you (generally) have to subscribe to to get them.
Until social media companies or their chat protocols are forced into some sort of interoperability - a thing we can do, under antitrust law - no amount of data portability will fix this. Because it's a consequence of their owning our networks, not just our content.
We’re definitely on the same page. I’ve been evangelising about interoperability for several years, meeting blank or glazed over stares the whole way. I’m definitely jaded.
For the most part I agree with what you say about big tech and their dominance, but you don't have to use their products for the most part. The web standards are the big problem in that context.
Genuine question - why do you feel you have to use TikTok?