I feel you. It's vey much a convenience thing, and sitting down with something you're used to.

yyyy-dd-mm 😀

Maybe you'r using an older version of Java? Works fine for me.

Do you fill with something other than the caesetes?

In Danish, it's said like 1st of June.

Didn't they just change to require meta account instead?

It's used for scripting. Apt specifically recommends against using it in scripts.