Is there any way to edit/customize the Breeze Widget Style of Plasma and if yes, then how can I customize it, is there any document/video/graphic/info available?

I want to change how the right click menu looks, animations on widgets, Button size and everything possible.

I can't find anything related to Plasma's default Widget Style. Also KDE userbase wiki doesn't have a document for Breeze style.

I already know about other widget styles like Kvantum, Qt Curve etc. Any help would be appreciated.

You can edit and customize everything, but not within a running style, you would need to make your modifications a new style.

The community wiki might be more useful than the userbase one, starting from here: https://community.kde.org/Get_Involved/design

The default Breeze style only has a limited set of configuration options which can be modified via System Settings -> Application Style -> Widget Style -> select Breeze and hit Configure.
The Breeze style does not support customization to the degree you are requesting, so further modifications beyond what's presented by that dialog need to be made by checking out the code for the Breeze style and making the code changes yourself.

The QtCurve style is much more configurable, and there are a couple themes available on the QtCurve section of the KDE store which emulate the Breeze style, which you can use as a starting place for your modifications.

You can find the breeze widget theme on github. However, I recommend kvantum which is super configurable and very easy to figure out, and is also fairly well documented. In a couple of hours I had a fully customized theme that I think looks nicer than anything I could find on store.kde.org. You can borrow from others themes. The most challenging part is getting the svg elements exactly as you want them for styling buttons and such.