Samsung phones have a low power mode on everything from s5 and up that disables every function of the phone (every sensor and radio) except texting and calling and 4 apps of your choice. It's much smarter to just disable your current phone than to completely replace it with something inferior and harder to use like an old flipphone. Samsung also makes modern flip phones running Android that have all the same simplicity of being able to be closed and of course not having apps installed if you so choose.