The Deck is configured by Valve in a way uniquely suited to it, and they also make sure it works properly. It’s not going to be the same on vanilla Arch installed by you on your own PC.
Common wisdom for a beginner is to use something like Debian or Debian-based like Mint or Ubuntu because they’re popular and stable so you can get a safe start. I wouldn’t recommend Arch or Arch-based to a complete beginner.