How can I reinstall a game using the existing data files?

I’d like to reinstall World of Warcraft. I manually installed it and it was working perfectly ever since I did so, but as of a couple days ago for some reason, it will no longer load. The game is 65GB to download so I’m wondering if I can reinstall the game using the already downloaded data files from the existing install? If there is a way to do this, can you please instruct me step by step? I’m an extreme novice with Lutris.

Through the app you can locate where you have downloaded your game data and the app will automatically update the game. You can do the same for other games from blizzard.

As for not being able to launch. Before you click Play right below it there are 4 icons. Click on Show logs and try to launch the game. It should give you some kind of output what is going on.