Hi! I’m really sorry, your post was pending due to having links and code. I didn’t realise I had to approve these posts. I do now!

Are you still having trouble? Does the port show up when the FTDI module is connected then disappears when disconnected? Are the connections to the Motherboard correct? Are you using a Short Circuits FTDI module or one from China (these could have different connections)? Is your ATMega328P connected the right way round? The notch in the chip should be on the right. Are there any solder bridges between pins on the ATMega328P or the FTDI connector?

A photo of your setup may help shed some light.

Sorry for the delay in approving the post. I hope we can find a solution to your problem.