The website of Bazzite says it comes with 'cpu-governors that are optimized for gaming'. A governor basically decides when and how to change the power level of your CPU. If a core is experiencing high load, it might increase power and clockspeeds to compensate. Of course this draws more power, so 'optimized for gaming' kind of means unoptimized for battery. I think most distros come with a 'power-saver' governor by default. This option should be available in power settings called 'governor' or 'power profile' or something like that.

Also, I recently switched from KDE Plasma (one of the Bazzite options) to xfce4 and I've seen massive gains in battery life, about 1-2hrs extra. I don't remember how many hours I used to get on win10 on this laptop, but I'm sure it has never been as good as this.