You have to be careful not to confuse / mix refresh rate (Hz) with frame rate (FPS).
PAL games should run at 50fps and at best on a 50Hz screen.
NTSC games should run at 60fps and at best on a 60Hz screen.
So for PAL games i would recommend to set the TV-Mode to 50Hz (if possible…. on RPi this works but on x86 it may depend on the hardware you are using… and it may also depend on the TV/Monitor you are using, wether it is capable of displaying 50Hz at the resolution you have set) and for NTSC games i would recommend to set the TV-Mode to 60Hz (should be default for the most modern TVs /Monitors (Flatscreen))
Depending on the Batocera version you are using, you should also check the RetroArch Video Settings, wether the Output Refresh Rate matches (50Hz/fps for PAL games and 60Hz/fps for NTSC games) and you may have to disable/enable Threaded Video for not having micro stutters and better performance on low end devices.