SK Hynix Inc. is a South Korean memory semiconductor supplier of dynamic random-access memory chips and flash memory chips. Hynix is the world’s second-largest memory chipmaker and the world’s 3rd-largest semiconductor company.
Looks like it has an OTC ADR but FT (DriveWealth) don’t have great OTC coverage. The ordinary stock in KRX won’t be easy until worldwide coverage gets greater. So you’re left with exposure via ETFs. Hynix is the 2nd biggest weighting on KRX so quite a few ETFs hold it
See here FinKi ETF Search