The Japanese version has FeliCa support, the global version doesn't. It is only softlocked however, so if you convert your global version to japanese lateron, FeliCa will work. Otherwise there seem to be no differences inside GrapheneOS.
EDIT: Don't buy the phone bundled with a cellular contract in Japan, japanese carriers sometimes bootloader lock the devices they bundle. If you buy the phone from a reseller, check whether the bootloader is unlockable before buying.