I am seeing some instructions on the net of how to set up automatic backups of iPhone to iTunes over wifi on home network. These are instructions on Mac, but I think Windows would be similar.

https://www.gottabemobile.com/how-to-set-up-iphone-wifi-backups-on-a-mac/

However, they use the word "Sync" here instead of "Backup". The terms tend to be interchanged a lot in iTunes documentation, but I don't think they're exactly the same. They do not make it clear what the difference is between Sync and Backup.

Some articles from Apple which don't really help clarify that issue, unfortunately:
https://discussions.apple.com/docs/DOC-8752
https://support.apple.com/en-us/HT204136
_________________________
Tony Fabris