They will set up a CDN for uploads on their platform that will track you like v.meta.com or i.meta.com.

This is the only thing they couldn't already do. They've probably already been datamining Fediverse users. No need to set up an instance for that.

I agree with the v.meta.com and i.meta.com. We'll have to establish some good alternatives by then so people don't use them just because they work so well.