My Polling Rate Shows 125Hz, Is That Why My Aim Feels Behind?

125Hz is not terrible and it is almost certainly not your problem, so hold off on buying anything.

The 1000Hz figures you have read about are overwhelmingly mouse polling rates. A mouse reporting a thousand times a second is meaningful because you move it continuously and a cursor tracks it pixel by pixel. A gamepad is a different device: your stick position changes far more slowly than a mouse moves, and almost every game samples controller input once per frame anyway. At 144 frames per second your game looks at your controller 144 times a second, so a controller reporting at 1000Hz hands it a lot of data it throws away. Beyond about 250Hz the returns on a gamepad fall off very steeply.

For context on your specific reading: an Xbox Wireless Controller typically reports around 125Hz over Bluetooth and closer to 250Hz over USB or the Xbox Wireless Adapter. So 125Hz tells me you are on Bluetooth, which your connection field confirms, and it is the expected figure rather than a fault. Plugging in the cable is the free experiment, and it will likely roughly double your reading.

On your aim feeling behind, I would look elsewhere, and in this order. First, the latency test, watching the spread rather than the average, because inconsistency is felt far more than a modestly low polling rate. Second, your in-game deadzone and response curve, which game patches reset more often than people realise. Third, frame generation or upscaling if you have either enabled, which adds delay that no controller test will ever show. Any one of those will move the needle more than going from 125Hz to 250Hz.

The honest summary: polling rate matters, but it matters least of the things on your list, and a controller sold on its polling rate alone is being sold on the wrong number.