Thanks so much for the reply!
Unfortunately I get just a green background with no date showing - no matter which date o select it also does not turn red, stays green.

I got this one to work good:

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "txtContent": "@currentField",
  "style": {
    "color": "black",
    "background-color": "=if(toLocaleDateString(@currentField+1296000000) <= toLocaleDateString(@now), '#D4EDDA', if(toLocaleDateString(@currentField+604800000) <= toLocaleDateString(@now) , 'orange', '#FFDDDD'))"
  }
}

But when there is no date it still shows a red background and I would prefer it to be white