I found the folder. Could you tell me what's the name of this game's save? There are really lots of files in that folder......
First I'll note that if you ever want to try and pull up these saves again, first back up the entire Artifact local storage folder somewhere else on your hard drive.
Then, you can delete the entire Artifact folder in this local storage (since this local storage folder is a completely separate location from the actual installation folder, meaning you won't have to redownload or reinstall anything), and then it's going to automatically be created anew the next time you run the game.