Nice sale with Lufthansa from across the United Kingdom to Buenos Aires via Frankfurt. Fares start at £1,337 and book into P class so be careful as they earn 0 miles in programs such as Aegean.
Argentina is still not open for tourists so in this Covid-19 environment it's up to your risk tolerance level whether you wish to book.
Here is a Trip Report with Lufthansa on their Airbus 380 from Frankfurt to Johannesburg and with an Airbus 340-600 from Munich to Newark.
Lufthansa Business Class