Changing the quality of items in the game

[Tekila]

Hello!  I've made pretty good progress in creating my own XML mods, but some ideas cannot be implemented using XML alone. I want to learn how to add my own custom C# scripts or edit DLL files inside the game.  I would like to change the quality of items in the game from 6 to 7-8 (similar to how it is implemented in Undead Legacy), but this is impossible in the quality file, as I understand it, you need to edit the code.  If there are knowledgeable people, tell me how to implement this or provide links to tutorials, guides and documentation with which I can implement my idea.  Thank you all in advance!