[2020] Achivemnets disabled. WHY?

Achievements should be available. Did you just create a character? If yes, is that character below the 400 points threshold?

I have justed tested it on my machine and I received an Achievement in Ironman mode.
When you are in-game, could you please open the menu and click on Achievements to check if Ironman is ENABLED and Achievements AVAILABLE?
Could you please also check if your version of CK3 is "Argent (1.2.1), Checksum d5f5?