If you need an OS and a cheap device use your old netbook or computer you have laying around instead of turning it into ewaste. You can do it all with a rpi zero if you insist on buying another device.
Agree. Old laptops have a built in UPS, screen, keyboard, active cooling, and can idle at very low power usage. Some machines even let you set a battery charge limit (say 50%) so the battery lasts for a long time without degradation. There are linux scripts around for this.
