Charlotte Doppler explains : "Every 33 years (...) The stars, the planets, the whole universe returns to the exact same position"
Only considering Saturn has a revolution period of 29.4 earth years, Uranus 84 years and Neptune 164 years, this 33 years cycle assertion can not be true. However, the "lunisolar cycle" she mentions does in fact exist. It is the underlying concept of the calendar in use today, which in turn does actually have a 33-year cycle: there need to be eight leap days within a 33-year period for the calendar to remain synchronized.
In a scene where Jonas and Bartosz are playing video games, the controllers are actually off.
When Hannah visits Mikkel's house to deliver food, Mikkel's sister Martha answers the door and her mother Katharina joins them. Five minutes later, Hannah asks Katharine where Martha is (implying she's not at home), and Katharina says she doesn't know.
Giving neighbors in distress covered dishes is culturally not a thing in Germany, at any rate not nearly to the extent that it is in the USA.