What is the difference between The Council of Europe and the European Union?

There seem to be two separate bodies which are trying to foment more collaboration and cooperation between Europe

1. The Council of Europe
2. European Union

There are a couple of links which try to explain the difference but are not very enlightening

• https://www.coe.int/en/web/portal/european-union
• https://www.differencebetween.com/difference-between-european-union-and-vs-council-of-europe/

Also, the EU has couple of bodies with similar sounding names:

• European Commission
• European Parliament
• Council of the European Union
• The European Council

Now some additional questions for more context in helping answer the main question:

1. Since, Council of Europe came first, why did it not metamorph into the European Union?
2. There seems to be significant overlap into what they are doing, then what is point of being separate? Why don't they merge?
3. Are these two competing bodies?
4. What are the exact separation of concerns between these two bodies?
5. Why does an international organization like OSCE has partnerships with both EU and COE?
6. What is the difference between The Council of Europe and Council of EU and The European Council?