I would suggest separate partitions for data/game installs if you want to try multiple distros without needing to reinstall your games. Just need to mount the partition in the new distro, maybe have steam scan it (or just set it as your game install location) and you're good to go. Encryption might complicate the steps, but I don't see much point in encrypting a game install partition in the first place.

Edit: Meant this comment to add on to your reply and address the "just set up a single partition", since you addressed the distro. On that note, I've been happy enough with Fedora KDE that I haven't even gotten around to trying a new distro (took me almost a year to try KDE and realize I liked it better than cinnamon in practically every way).