According to YouTuber Dave2D who managed to get their hands on the Lenovo Legion Go S, the SteamOS version destroys Windows in performance and battery life.
I haven’t tracked the performance in Proton for a long time, because I already used that information to make my purchasing decisions, but single digit percentage improvements in performance when running games via Proton has also been the case on desktops for a long time. If there’s any further improvement to be seen from SteamOS’s game mode rather than regular desktop, you should see it in Bazzite as well.
Dual booting has existed for a long time but this same boost in performance when using SteamOS might not appear on desktops.
I haven’t tracked the performance in Proton for a long time, because I already used that information to make my purchasing decisions, but single digit percentage improvements in performance when running games via Proton has also been the case on desktops for a long time. If there’s any further improvement to be seen from SteamOS’s game mode rather than regular desktop, you should see it in Bazzite as well.