Why not get a phone with long battery life, like some of the cheap androids from companies like unihertz or a Nokia with keios. Then forward automatically all

Why not get a phone with long battery life, like some of the cheap androids from companies like unihertz or a Nokia with keios. Then forward automatically all calls to your voicemail that just have a message saying this number don't take calls. Then use sms or any messenger of your choice.