How to dislodge or realign stuck volume dial/slider of an Arctis 7+

First, identify the side you're removing the cups from. The volume side one is the left one with the hardware mute button, so this shouldn't be too hard.

Remove the cup by inserting your four fingers in the inner ring of the cup, with your thumb softly pressing against them from the outside. Slowly turn it clockwise/counterclockwise while pulling up, and the cup should come off. If you need help doing this part, there are plenty of YouTube guides for this step, as this is universal for Arctis units.

With the cup off, now you need a Torx TR6 bit to remove three screws. This is relatively easy, but do be careful when removing the lid, as there is a wire connecting it to the pcb housed in the body.

Now is the last part. You'll need a Phillips 00 bit for this, as you must remove two screws to "free" the PCB.

Once unscrewed, you *don't* need to remove the board, but just try to gently pull it up along the upper-side (nearer the headband) to re-align the volume slider back into position. Slide the volume knob after every tug upwards and see if it's re-aligned.

You shouldn't need to remove the PCB, and you probably won't want to, as re-attaching it means you have to re-align the volume slider, hardware mute button, 3.5mm jack AND the two USB ports. While it is doable, it is not necessary for this specific technique.

Once the slider starts running smoothly back and forth again, this usually means the slider has re-aligned its center axis back to the volume control unit. Re-attach the screws and the upper plate with the cups, and try connecting it to your PC and check if it's working again.

In case you didn't see it from a YouTube guide yet, I've included a short demonstration of how to re-attach the cup back to the headset. It's not as complicated as it looks, as Steelseries actually implemented a nice "hooking" system for your cups to slide into.