GTA Online is no longer officially supported by Steam Deck, this is actually due to the introduction of some anti-cheat software that can be made compatible with Steam Deck. What do you say now?
Rockstar added BattlEye Anti-Cheat to GTA 5 and GTA Online in an update on Tuesday, September 17, adding options to disable the anti-cheat for the Story Mode game in the Rockstar Games Launcher or third-party launchers. In the process, support for the Steam Deck game has crashed like a police helicopter in a traffic jam.
“Steam Deck does not support BattlEye for GTA Online,” the changelog clearly states. “You will be able to play GTAV Story Mode, but you will not be able to play GTA Online.”
It's a bit odd because, as The Verge points out, it's been possible to get BattlEye to run on Steam Deck for years, but the Linux-based operating system doesn't support it by default thanks to the Proton Windows compatibility layer. Apparently, it's as simple as sending an email to BattlEye's resellers. As PCGamer adds, GTA Online is or was one of the most-played Steam Deck games, so all of this is a bit of a problem in Los Santos.
Rockstar has laid the blame for the loss of compatibility at Valve’s door in its changelog. “GTAV and GTA Online are not officially supported on Steam Deck and all technical support questions should be directed to Valve’s Steam Deck support content and community,” it reads. Players are doing just that. One reddit user claims to have heard from a Valve representative that they are “working with Rockstar Games to find a solution.”
I'm honestly a bit confused, but there seems to be some hesitation from major publishers about whether or not they'll support anti-cheat software on the Steam Deck's Linux-based operating system. Presumably, if you dual-boot Windows on the Deck and skip the Proton layer, you'll still be able to run GTA Online.
If there is one thing everyone can agree on it is that GTA Online has a cheating problem. I wonder how they will address this and GTA Online in general after the release of GTA 6.