How do I automatically back up iPhone to iTunes?

This used to be a feature, I swear, but I haven't seen it lately.

I would like to back up my iPhone to my desktop computer each night, without connecting it, just over the shared wifi they they're on. In the past, I could set this up assuming they were on the same network, the phone was charging, and it was some chosen time in the wee hours of the morning.

To be clear: I want to do this locally on my Mac Mini, not to the Cloud. I have Cloud backup turned off.

Bonus points if it can be an encrypted backup so all of my passwords are stored.

If this is still a possibility, I will want to do this with all phones and iPads in our household, so thanks for any help.