That's gonna depend on the distro and kernel, as different ones have different drivers, different power saving things, different apps. In general all modern distros should have decent support for power saving out of the box, but things like wifi cards typically have crap/buggy drivers when it comes to power saving (but again it depends on the hardware and driver)
That said, the spec sheet MobileMark benchmark says battery life is as good as 14.3 hrs in max battery setting on WUXGA Low Power (non-touch), Win 11, 52.5Wh battery, versus a performance mode getting 5.0 hrs on 2.8K OLED (non-touch), Win 11, 39.3 Wh battery. With 'local video playback' lasting longer. So I guess it's very hardware and use-case specific. (https://psref.lenovo.com/syspool/Sys/PDF/ThinkPad/ThinkPad_T...)
Eight or ten hours? I don't take a power cable with me for the day. Would probably be better if I worked out how to set any of the power saving things, this is Debian out of the box. That's mostly showing emacs, I expect it would be worse with a browser.
I'm on a Zen3+ APU (Thinkpad Z13) and TLP has worked great for me. TLP has nice out-of-the-box defaults so you don't need to tweak anything if you'd like, but you may need to disable any existing power management systems, if you're using a full-fledged DE, as they could conflict.
Two cool things that TLP does is allow you to set battery charge thresholds for better battery longevity (I limit mine to 80%), the other being automatically changing the energy performance preference (EPP) in the amd-pstate driver, so if you're on battery you could get it to automatically switch to power saving or balanced powersaving etc. I get an 8-10 hr battery life even with the 80% cap capacity, with several MS webapps running in Edge (Wayland), including Teams and Outlook, VS codium and Firefox running in the background.
That said, the spec sheet MobileMark benchmark says battery life is as good as 14.3 hrs in max battery setting on WUXGA Low Power (non-touch), Win 11, 52.5Wh battery, versus a performance mode getting 5.0 hrs on 2.8K OLED (non-touch), Win 11, 39.3 Wh battery. With 'local video playback' lasting longer. So I guess it's very hardware and use-case specific. (https://psref.lenovo.com/syspool/Sys/PDF/ThinkPad/ThinkPad_T...)