DFlex has an infinite transformation mechanism even between containers. So you can transform indefinitely and if you want you can enable committing to DOM which will trigger a custom reconciler built specifically for transformation. It's also not just for React, you can hook it with your JS framework.
Yeah that statement is simply not true. Manipulating the DOM was how all of this was done already in the before jQuery days, not to mention many, many libraries since.
I'm not sure this is the only library doing this. It's in fact a popular approach for drag and drop on the browser. I believe dndkit also does this.