I've had the complete opposite experience (I replaced their Pop OS with Arch Linux). With light usage I get about 10 hours, if I'm playing games or something then yeah it drops a bit but not that much. It easily lasts the duration of an intercontinental plane flight which is my primary use-case.
Maybe it's because I don't actually use it all that much, so my battery hasn't had many cycles put on it. I only use my laptop for travel, normally I have a desktop. That's why I went for a small, highly portable model.