The thing is, you two are talking about the same wedding but with completely different visions, and that's a real problem that goes beyond whether you stream it on TikTok or not. Before you dig in with a hard "no," you need to understand what's behind this for your girlfriend. Does she really care about getting recognition from strangers, or does she just want to share something she thinks is beautiful with as many people as possible? Sometimes people confuse going viral with connection, and that's definitely something you two need to work through together.
What you didn't mention before is that if you go along with this without actually being comfortable with it, resentment is going to seep into the whole ceremony. You're going to be thinking about the cameras, she's going to be glued to the live comments, and in the end neither of you is going to actually be present at your own wedding. That's way worse than any awkward conversation now.
Propose a middle ground that's honest: maybe you can record some moments to share afterward, on your own terms, without it being live. Or have a small, intimate ceremony, and she records whatever she wants after for her content. The point is your peace of mind on that day shouldn't be sacrificed for algorithms. If she can't understand that, then there's a deeper issue you need to work out before you get married.