I am trying to unwrap a fireplace model. I have marked the seams wherever required but when I try to unwrap it, all the edges of the model are at an angle and are distorted as you can see. I want all the edges to be perfectly straight.

I've already applied the scale in the object mode. Any help is appreciated.

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/k75Ms.png