Remember the good ol' days when we used mobile phones to actually talk to people, and batteries seemed to last forever? Well, those days are not over my friend. You just need to get used to using your brand new multi-core multi-band multi-GHz multi-GB smartphone as an old dumbphone. Like I did last week.
Just light texting and talking. The bare minimum. No 3G. No 4G. No 5G. No WiFi. No Bluetooth. No GPS. No NFC (who uses that anyway :-p). And of course, no gaming!!
I'm proud of my frugal smartphone :-D