Don't use rechargeable batteries. See if you get more longevity from alkaline batteries. I can go for months with a trackpad, cordless mouse or Bluetooth keyboard and alkaline batteries.
On a Mac since 1984. Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.
