Can be iPhone used to burn CD/DVD? Is it possible to burn CD/DVD with iPhone and USB CD/DVD Writer?

I have a camera module for the iPhone to make it as if it has USB female socket instead of lightning one.

I’ve verified it works for my portable keyboard (musical instrument) to send signals to GarageBand nicely. The module also includes another port for a power supply!

It was once a problem for iPhone to transfer any data to different device before the Files app became available, but it is not now, I assume.

That being the case, is it possible to transfer data stored on an iPhone to a CD/DVD using the camera module and CD/DVD writer?
The Apple Lightning to USB adapter is not powered, so the trivial answer is no. As you've already realized, many powered pass through USB devices exist and some surely have enough power For most USB bus powered devices - even a motor and optical drive.

The slightly more complicated answer is also no. The software interface and software drivers to recognize a burnable media device isn't programmed into iOS (or iPadOS).

All your good work connecting the device will be for naught without software changes. I bet someone with a jail broken phone and skills could cobble together open source drivers and attempt to load them, so I'm not saying that this isn't theoretically possible, just that it's not plug and play due to software issues and potential power issues.