Yes you can connect keyboard and mouse; Overwatch (https://www.protondb.com/app/2357570) and WoW (https://appdb.winehq.org/objectManager.php?sClass=version&iI...) should both work well, as do the vast majority of single-player games. Some multiplayer games with particularly invasive anti-cheat may not, so if you have anything else in mind best to check before buying.