The Arch Linux wiki is the best resource for all things Arch, including documentation for almost every built-in function and even 3rd-party ones, as well as an AUR package search and more. Check the wiki first for any issues you're having or possible functions you may be trying to find. Sometimes it'll be right there.
ProtonDB is one of many sites that help gamers figure out if a game should be runnable on Linux, and if so, what different people have tried to get it to work properly. While it's not meant to instantly solve game issues, it can give you some insight into what you may be doing wrong or things you may not have tried. Note that even if someone says the game works, it may not work for you for one reason or another, and the opposite is also true; your game may work perfectly while others are struggling to get theirs working.