Laptops with Intel Lunar Lake (i.e. 258V) CPUs get upwards of 12 hours easily, often in 15-18 hour range depending on the battery size. Just a quick search reveals for example Dell XPS 13 9350 (Core Ultra 7 258V) is Ubuntu certified [1], weighs 2.6 pounds, and has long battery life (17-18 hours video streaming on Windows).
Lunar Lake laptops throttle a lot when unplugged. They run benchmarks plugged in and in maximum performance mode but battery benchmarks in max battery mode.
True, but the throttled performance on battery is enough for office work / coding / browsing workloads. Is it matching Apple silicon, probably not. Is Linux matching MacOS on SW/HW optimization? Probably not either.
[1] https://ubuntu.com/certified/202407-34214