In the end = finally. It is often followed by a comma. For example, I worked hard, in the end, I was tired. At the end is similar to 'in the end' but it is often followed by OF to refer to the end of a specific noun. For example, at the end of the film, at the end of the day, at the end of my journey, etc.

In the end=finally (we use it when we want to finish a talk or a speech) At the end we use it like (at the end of the street,at the end of my work . ,etc) I hope you get the idea

Thank you

I think Finally and in the end basically mean the same thing; I didn't hear ppl use 'at the end' except in the phrase 'at the end of the day', which is used by Australians everyday