League Client only works after reinstallation

Haven't played LoL in a few years. Decided to give it a try. The game installs and runs fine until I close the client. Clicking the shortcut added to the desktop shows the little splash screen and then it closes. Taking a look at task manager 3 executables show up then drop off. There is no bug screen or error message, just closes. Clicking the EXE in the game folder does the same thing.

I've tried a number of possibilities, including a fresh install of the game to a new folder, deleting random files/folders in other threads. The same thing happens.

I can reinstall the game over top of itself and it takes a few minutes but it works if I do that for whatever reason. I don't even have to launch the game to cause another failure, I can just close the client and then it doesn't work again until I reinstall.

Pretty lost what to do next.

Thanks!