Using a 4g/5g router? This phone setting could save you a few quid

We have a 4g router at our static caravan, which I top up each month. At some point in the last day our iPhones auto-downloaded updates and used most of our monthly allowance in one pop. Turns out there is a “low data” setting that you can enable for a particular WiFi network in iOS settings - would have saved us a few quid! Presume Android has similar.

Would have been nice if it was enabled by default for 4g/5g routers, but I don’t know how.