Confusing English series : At the End (vs) In The End

Confusing English lesson series. Today, we're going to explore the difference between "at the end" and "in the end."

We use at the end to convey the meaning of at the time when something ends.
Let's consider the following examples.
Nadia always feels tired at the end of the day.
My grandfather became very sick at the end of his life.
However, in the end is used to say what the final result of a situation was.
Let's consider the following examples.
Adam was very stressed about the sales, but in the end he relaxed .
At first, The board didn't accept Bob's proposal. Bod tried hard to convince them. In the end, they accepted it.