Every time I open the game, all the settings reset, even the resolution.

So every time I go ahead and open my game again, since I redownloaded it yesterday, all my settings reset, including my resolution, sound settings, I even need to accept the agreements and stuff again. And username is not remembered. It's kind of getting frustrating.

You need to remove "Read-only" from game folder. Place it where you have permissions to change it.