Offline options / synchronise on WiFi only?

I am on a low data plan. But have got good WiFi at home. I miss a function in general settings where I can turn to ‘offline’ as soon as I am out of WiFi range. Every time I set a new trap on the app connection is made and when I am in low reception this chewes battery and data.
To me it is good enough if all data are synchronised once I am at home with WiFi.

Thanx for any thoughts on this one.