How to buy the 70th Anniversary DLC for F1 2020?

Hi,

I would like to ask how do I buy the 70th Anniversary DLC for F1 2020 game for PC?

I tried checking Steam but it seems the game and DLCs have been pulled out since the game itself was released long ago. For context, I own the base game in Steam.

Any insight on how I can get my hands on the 70th Anniversary DLC for F1 2020 game for PC would be much appreciated.

Thank you.