How a shovelphone is better? The author mentions 5 days is great battery life. My old dumbphone with halfdead battery has 5 days life, and it's short, used to be 15 days or so.
I don't know how things are these days but when I was doing the digital nomad thing I had an old android with my home SIM in it in order to accept calls if anything important came in, and just by disabling data and wifi it would last a week on standby. Smartphones have huge batteries that they waste on keeping always-on TCP connections going. Remove those and it should last forever