So why in the world would you have smartphone at all with that usage pattern? A Nokia 3300 would be sufficient! ??????
Purposes: emergency phone when away from the house and in my car, playing music (Amazon) when walking the dog and shopping in the supermarket; reading Amazon eBooks when away from the house; sending and receiving text messages with the family. Most of my actual phone calls are made from the house using a copper wire like with a base and 4 wireless extensions..
Even those, who use the apps aggressively, would benefit from use Ultra Power Saving Mode when not using the apps. They can still make and receive phone calls and text messages in that mode.
Finally, that Mode ends app activities which may have been running out of control after an update.
In that mode