I wonder if the difference with tiktok is that there are thousands of videos about the same thing, everyone sees a few of those thousands, but they see a different few. So even though we're sharing the feeling, culturally, we're not sharing the same artifact.
Like maybe the trouble is that tiktok puts each user into their own custom bubble, and the bubble the user finds themself in is completely opaque - you can't readily compare what you're seeing to what your friends are seeing?
As for the sculptures and paintings of Mary, etc., I'd say they are all boring and entirely interchangeable, but that's because I have no connection to any of them. Each such work is meaningful to the community that had a personal connection. But I'd say none of them are culturally important, except those individual ones that for some reason (like being very old) become widely known among people outside artifact-adjacent community.
Side point: culture always has a scope. Something may be important cultural object for the city I live in, unremarkable for anyone else in my country, and entirely unknown the rest of the world. With the Internet enabling arts and entertainment on demand, there is little overlap between communities we live in and the entertainment choices of individual community members. We end up having communities with no culture.
What makes it "not culture" is that everyone is watching one or few of those hundred thousand fully exchangeable tiktoks.
A thing which is basic, vague and shallow can become an important cultural work too - it just must become known to approximately everyone in a society. It must somehow become the one representative work in its class, so that when someone makes a reference, everyone knows exactly which work is being talked about, and that everyone else knows it too. Being unique is not strictly necessary, but is highly helpful.