SteamDeck

Prerequisites

• Bottles

Setup Instructions

• Since Bottles is a Flatpak, you'll need to run a simple one-liner in a terminal to grant it filesystem access:
  

flatpak --user override com.usebottles.bottles --filesystem=host

• If you're using an SD card or any other (external storage), additional lines are needed per device:
  

flatpak --user override com.usebottles.bottles --filesystem=/run/media/deck/[name] (Replace [name] with whatever the card is called)

• Then download and install GTA Connected in Bottles.
• Use the built-in "Add to Steam" option in Bottles to add GTA Connected to Steam.

Notes

• It's much easier to install in Bottles than adding it directly in Steam.
• There are alternatives to Bottles, such as Lutris or adding the GTAC installer as a non-steam Game, but the latter requires changing the EXE to GTAC launcher afterwords.