Counter strike works well on the deck.
Insurgency sandstorm works well on the deck. Needs to be plugged in as it goes through battery fast.
Battlebit Remastered is the latest that works well. Remap some buttons and it’s great.
I use gyro aiming on all of these (turns on with using L2 for aiming.)
Getting other launchers to run can be tough so that’s probably why you’d think it won’t work. But to me it’s not worth the effort.
I’d go with emulating. Any PS2 FIFA game will work great. I’ve gotten WiiU roms to run well. People have gotten Switch games to work (I tried BotE but I need to organize the game files on a separate computer first and see if I can get it to work.) PS3 was a hassle to setup and won’t even work after hours of setup. Ymmv.
There are some indie games on steam you can try as well but they are more arcady.
Emulation of PS2 has been flawless. The setup is easy and you can get good looking graphics (I’m playing ratchet and clank series right now. 1080p makes the models look really nice. )
PS3 has been near impossible for me to get running on my SteamDeck. Others have said they got it working with titles being hit or miss.
Is your profile a Pac-Man influenced flyers logo?
Yeah the deck takes practice to get semi decent in fps. I’ve been trying to research if it’s possible to counter recoil movements in game with the deck controls. Nothing yet but maybe someone will figure a work around.