Sorry, I misread your comment, I thought you were asking for a method other than one using lockdown mode. I doubt there’s a method using location if it isn’t provided by the manufacturer, because an app trying to do that would need permissions to lock the phone.
For almost any phone: just turn it off. Every phone I’ve used requires a passcode after a power cycle
That’s not really related to what I asked though…
Sorry, I misread your comment, I thought you were asking for a method other than one using lockdown mode. I doubt there’s a method using location if it isn’t provided by the manufacturer, because an app trying to do that would need permissions to lock the phone.