I am running Sway on a Gentoo on a 4 years old X1 carbon.
> you will get similar usable battery life of around 6-8 hours
My macbook M3 gives me way more than 6-8 hours, it's simply insane. It literallly lasts for multiple days.
> Generally though, battery life isn't an issue anymore considering fast charging is everywhere.
Not an issue indeed, I got used to always charging my X1 carbon. But then I got an M3 for work, and... well it feels like I don't have to charge it ever :-).
As I said: very much a Linux person, but the M3 battery life is absolutely insane.
Run a lightweight DE like i3wm with any modern thinkpad and you will get similar usable battery life of around 6-8 hours.
Generally though, battery life isn't an issue anymore considering fast charging is everywhere.