I don't think it's entirely TikTok. In my view it's the best Disney film since, at the very least, Moana. The fact that so much of the film deals with relatable family dynamics that a lot of people can connect to doesn't hurt. While I don't think it's Lin's best-ever score, I don't think it's a poor one by any stretch.
It's too early to tell how much staying power the film will have in the long run, but in my circles the film is still readily being talked about more than a month after it was put on Disney+ and more than two months after it was released theatrically. I'm seeing far more chatter about the film from people who don't usually go to animated films than I have with any film since Frozen. People have been pointing (and will continue to point) at box office numbers to slight the film or fit a narrative they want to push, but that ignores the fact that no matter how much people wish it to be so, the movie theater industry has yet to demonstrate full recovery outside of a handful of movies featuring mega-popular IP. It's not an apples to apples comparison the situation facing a film like Tangled.
I do think it's weird that Disney doesn't, at the very least, put the characters in the parks to promote the films anymore or seemingly prep more than the bare minimum of merchandise for their new film. They were still doing that as recently as (at least) Big Hero 6. But ultimately there are signs, in my view anyway, that the film will have legs and staying power. The real question for me is not whether there is staying power with the film but how long and how intense the staying power will turn out to be.