Legion Go S performance to battery expectations

Hi so I just got this Legion Go S (SteamOS) Z1E 32GB about week and a half ago really liking it for the most part but I've been sort of perplexed in the sense I'm not sure how to optimise game settings to get max battery while also not making the game look dogshit.

Like I'm mostly talking about older games here for RDR 2 I managed the settings to get to stable 60fps and good visuals and it gives me like 1.5 hr performance which I find acceptable in exchange for the quality I'm seeing but then there are other games like trails of cold steel, a PS Vita game that if I wanna hit stable 60fps at High settings I only see projected battery at like 2hrs? Just seems really unusual to only get like 30 mins more as compared to something like Red Dead id expect at least 3hrs for such a old game.

Same goes for a game I just tried Yakuza 4 remastered 60fps at 15TDP 1800 clock speed I'm getting like 2.5 hrs projection is this normal?