You're lucky, my thinkpad x13 gen 2 AMD gets 5 hours on modern Fedora vs. 9 or 10 on Windows.

I also have an X13 Gen2 AMD. My idle power consumption is 2.5W to 4W depending on brightness. This ends up in 12h-15h (machine/battery ist 2y old I think).

I think you can improve your power settings.