Check the usual culprits... Bluetooth / Location / Resolution settings. Mine on native 1080p will give me roughly 8 to 10hrs if i game a bit as well.. 720p almost a full 24hr cycle.

Clear the app cache on the apps that crashes. If all else fails do a system reset.

Do a Battery Diagnostic . Mine is about 3yrs old and yet my battery lasts thr whole day. Have to add my OS is highly tweaked

Run Game Launcher -> More -> Game Plugins. Look for any enabled / installed plugin in the list and simply uninstall them like any other app in Settings or disable them in the menu. More than likely Perf Z and Priority Mode plugins are active.