Comment by nextos

> If someone has suggestions please share

A recent ThinkPad with one of the latest AMD Ryzen U CPUs should have a very decent battery life. You just need some custom udev rules to set the right power saving states for different devices. Powertop should make this straightforward. IMHO, this is a great compromise, because you stay on x86_64 and Linux, you get within 3/4 of ARM's power efficiency, and hardware support is perfect. I've squeezed more than 11 hours from some models.

One thing that is often discounted is that Safari is marvel of power efficiency, which adds up to the efficiency of Apple M chips. IMHO, there should be dedicated Chromium and Firefox builds with compile flags and options that optimize efficiency. To counter that, running a barebones Linux setup is a good option. Keeping your CPU wakeups/s low lets you cross the 10 hour barrier.