Another case of having luck and being at the radio at the right time and frequency: I saw a few stations from South Korea show up in FT8. Tried making contact with more than one of them and the second or third station became stronger after a few minutes and with some trying the contact was made with HL5BLI. It was a really short opening, five minutes later I saw no traces of stations from South Korea. Update 2021-04-05: And the contact is confirmed on Logbook of the World too.