There are no grammatical mistakes in your translation, but it is too Chinglish, completely Chinglish, especially blunt, and cook mainly indicates action, which is very strange when used in completion. Downstairs, I have finished eating, which is generally used to indicate that you have finished eating. Life dialogue had better be concise. Dinner is ready. Come and get it. Dinner is ready. Come and eat. Is it much better?

We will go home soon, please prepare dinner.

4. How does his cooking taste?

5. It's delicious/delicious.