Hi,
My name is Tanmaya, I have more than 7+ years of experience in development of enterprise and e-commerce applications using Magento 1 and 2.
I have done these type of jobs, many a times with multi channel concepts along with creating ougoing order custom feed using XML, JSON, CSV , GOOGLE SPREAD SHEET and even FTP to upload based on a timing trigger using CRON, so I do have full of experience in developing such thing for you.
share your sandbox details, will write the code to generate that XML on my server , and show you the demo.
Code will be written with all security and performance measures and will be delivered on time.