I'm not sure how much you like to tinker
@KEW but when I decommission old phones and relegate them to other duties, I always find a lightweight third party firmware. This will allow you to maximize battery power and control/uninstall more apps. It could be tough with a phone that old, but you could check old CyanogenMod (now lineage OS) builds. As a disclaimer, this is a pretty involved process...not for everyone!