Are the Business Central APIs truly the sole tools available for doing Deep Inserts?

The Business Central web services must be used to simultaneously insert headers and lines. However, the lines cannot be entered; only the header can.

I discovered that Deep Inserts can only be performed through the APIs when searching online for information about this issue.

I looked through Microsoft's documentation in an effort to locate a piece of writing or other reference to this, but I was unable to do so. I start to doubt if using the APIs is the only way to do this.