Stick with mouse and keyboard… steam deck has usb ports doesn’t it?

There are a lot of good suggestions here, that you can take advantage of, so I’ll come at it from another perspective.

With mouse and keyboard, positioning is a snippet of what we use when playing and is more of a tactical spacing. With controller, it is a necessity. This means that as you are playing first person shooters (or third person with controller), your characters movement will be 75% of what you’re actually aiming with.

On a mouse and keyboard, if you’re slightly off center with a sniper, it’s a simple adjustment to move to the left. Move 1cm.

On a controller, if you’re slightly off center, suddenly it isn’t as simple, because the joystick is overly sensitive and so to move 1cm is a lighting fast action input, meaning that you’re almost guaranteed to overshoot it, unless your joystick sensitivity is super low. Or, on the opposite end of it, if you try and move the control stick very gently (more on this later), it’s not necessarily a consistent input. This is where aim assist would come in, as aiming down your sights would center it on the enemy, but I think it’s a bunch of bullshit and so we’ll ignore that. Instead of moving the joystick a micron of a second to properly position yourself, moving your characters body (WASD/left analog) is almost always much slower and fine tuned.

What this means is that as you’re playing games, instead of holding W and maneuvering with A, S, D for counter balance or strafing or whatever, the joystick instead is 60% of the time holding forward, 20% of the time slowly moving in a direction to position yourself better for aiming, and 10% staying still (letting go).

Another element here is the concept of analog itself. When you’re holding W, it’s always 100%. When you push forward, (game depending) it ramps up from 0% towards 100%, which means that if you turn left or right, chances are that your character might slow down too, because you may be pulling down as you move. What you can take advantage of here is utilizing slow movement to always keep your character moving, which will help prevent being hit and will get you more used to fine-tuning your aim through your movements.

When I play games on controller, I always try and use gyro, I always keep the gameplay focused on the movement first and foremost, and the analog stick at that point almost purely becomes a look/view stick over a “this is my main form of getting headshots”, where your look inputs are based on getting into the center of the general area you want to aim at as quickly as possible, while letting the gyro and the characters body finish it off.

Finally – PLAY. Not the game, PLAY with it. Feeling weird? Move your character in circles while bunny hopping to get the feeling of the mechanics for the game, then be silly with the aiming and wiggle the joystick around to familiarize yourself with aiming with the movement wobble. Whether it’s Max Payne, Smash Bros, Doom, Vanquish, Fortnite, all of these games can be manipulated by playing with the weird quirks of their engine.

Finally finally – I also have a harder time with FPS games on the Steam Deck compared to other methods. Doom 2016 on my Switch was fine to get used to, but on the Steam Deck some did feel odd about it. I don’t have the other modern consoles and their joysticks aren’t super familiar to me, but I think it may be that the Steam Deck’s analog sticks feel like they have a larger travel distance (particularly compared to the Switch of course). Something you might consider trying is the Flick Stick input for the Trackpads, although I personally really, really enjoy low-friction trackball mouse input. Swipe+Tap to aim is just so good and being able to move the view, let go and have it keep moving based on the intertia I input is just perfect.

Try experimenting with gyro aiming. It feels weird at first but becomes natural soon after.

Moving a joystick is fundamentally different to moving a mouse. With a joystick there is a spring constantly acting to center it - no equivalent force when using a mouse. So you need to get a feel for estimating that force and accurately counteracting it in various gameplay scenarios. That’s a completely different “muscle” to have a memory of vs. using a mouse I think

Also, modern controller joysticks generally are not great. Most have medium to large deadzones in the center by default. I’d recommend reducing them for more responsiveness. It comes with the tradeoff of being more susceptible to stick drift. But that isn’t something you should be afraid of. It’s a physical impossibility for their design to not wear over time. I’d recommend recalibrating and adjusting settings regularly. At the end of the day, replacing joystick modules only requires screws (no soldering) so it’s cheap and relatively easy.

If you’re really serious you could get some hall effect joystick modules. That way you wouldn’t need to recalibrate often and could keep a consistently small deadzone setting without encountering drift. i.e. default settings from like dualshock 2, when stick drift was just as apparent but people hadn’t gone crazy over it yet.

Minecraft would be fine for learning fps movement in a relaxed setting.

I mean, twin stick gamepad or to lesser extent touchpad just isn’t going to be as good as a mouse for an FPS. A good mouse player will beat a good touchpad or gamepad player.

And the problem with the Deck is that it has a PC game library, and a lot of those are designed with a mouse in mind. Console FPSes usually adjust the game difficulty so that playing with twin sticks are practical. Enemies give you more time to slowly turn around without inflicting enormous amounts of damage. Auto-aim assist is common. Ranges are shorter. Stuff like that.

If this is a single-player game – which it sounds like you’re playing – you can reduce the difficulty to compensate for the input mechanism.

There’s an input mechanism that some people developed for twin-stick gyro controllers called Flick Stick, which someone else mentioned; Steam Input supports this. The mouse is still going to win, but it’s an improvement over traditional pure-stick input.

There’s also some input mechanism which I think was different from the “Flick Stick” approach – though maybe I’m wrong and misremembering, didn’t have an interest in exploring it – that IIRC someone put together using Steam Input. The way it worked, as I recall, was that one could tap the thumbstick in a direction and it’d immediately do a 90 degree turn. The idea was to provide for a rapid turn while keeping sensitivity low enough to still permit for accurate aiming. But I’m not able to find the thing with Kagi in a few searches, and it’s not impossible that I’m misremembering…this was only a single video that I’m thinking of.

I don’t think that there’s any trick to learning this, just playing games and picking it up over time. I mean, I was atrocious at using a keyboard+mouse when I first started doing it, and ditto with twin-stick FPSes.

You could also attach a keyboard and mouse, though I think that that kind of eliminates the point of the Deck, at least as long as one also has a PC to play on – it might make sense for someone who just uses a Deck and a phone.

is there an easy FPS game where I don’t have to move or shoot too fast

Play games that are designed for consoles or which have a gamepad mode, rather than a keyboard+mouse PC game. They’ll be tuned for controller limitations. Like, can you play Halo comfortably with the Deck? That was designed for a gamepad originally, and it’s available on Steam (though I’d note that it requires a Microsoft account, which you may-or-may-not be willing to do).

https://old.reddit.com/r/truegaming/comments/8f7oyr/the_core_reasons_thumbsticks_are_inaccurate/

This also talks about some limitations of thumbstick aiming (if you’re using thumbsticks and not trackpads). It might be possible to tweak some of these, like sensitivity or dead zone, but I’d assume that for a given game, the developers have already chosen pretty reasonable defaults.