There are a lot of interesting things in your post.
First, League typically doesn’t work well on Linux because Riot doesn’t care about Linux users. If League is going to be a deal breaker, I’d recommend getting a dedicated Windows system for the best time.
Second, your CPU has a known hardware bug with C-states. If you’ve been noticing your computer freeze often under Linux, disable C-states in your BIOS.
Third, are the games you’re trying to launch purchased through Steam, purchased through a different store, or pirated?
Are you able to play any of your games, or is it just these few that have been giving you trouble? If it’s every game, you may not have the nvidia driver or vulkan installed. Just to be sure, you can try running nvidia-smi in a terminal, which will show you which driver the system is using. If you are unable to run the command at all, you’ll definitely need to install the nvidia driver